John C DeFries

Articles

DeFries, J.C., Touchberry, R.W., & Hays, R.L. (1959). Heritability of the length of the gestation period in dairy cattle. Journal of Dairy Science, 42, 598-606.

DeFries, J.C., Touchberry, R.W., & Hays, R.L. (1960). Changing the length of the gestation period in dairy cattle. Illinois Research, 2(1), 19.

DeFries, J.C., & Touchberry, R.W. (1961). A "maternal effect" on body weight in Drosophila. Genetics, 46, 1261-1266.

DeFries, J.C., & Touchberry, R.W. (1961). The variability of response to selection: I. Interline and intraline variability in a population of Drosophila affinis selected for body weight. Genetics, 46, 1519-1530.

Weir, M.W., & DeFries, J.C. (1963). Blocking of pregnancy in mice as a function of stress. Psychological Reports, 13, 365-366.

DeFries, J.C. (1964). Prenatal maternal stress in mice: Differential effects on behavior. Journal of Heredity, 55, 289-295. Reprinted in M. Manosevitz, G. Lindzey, & D.D. Thiessen, Eds. (1969), Behavioral genetics: Methods and research (pp. 528-537). New York: Appleton-Century-Crofts.

DeFries, J.C., & Weir, M.W. (1964). Open-field behavior of C57BL/6J mice as a function of age, experience, and prenatal maternal stress. Psychonomic Science,1, 389-390.

Touchberry, R.W., & DeFries, J.C. (1964). Genetic effects of gamma-irradiation on egg production and adult emergence of Drosophila melanogaster. Genetics, 49, 387-400.

Weir, M.W., & DeFries, J.C. (1964). Prenatal maternal influence on behavior in mice: Evidence of a genetic basis. Journal of Comparative and Physiological Psychology, 58, 412-417.

DeFries, J.C., Weir, M.W., & Hegmann, J.P. (1965). Blocking of pregnancy in mice as a function of stress: Supplementary note. Psychological Reports, 17, 96-98.

DeFries, J.C., Hegmann, J.P., & Weir, M.W. (1966). Open-field behavior in mice: Evidence for a major gene effect mediated by the visual system. Science, 154, 1577-1579. Reprinted in M. Manosevitz, G. Lindzey, & D.D. Thiessen, Eds. (1969), Behavioral genetics: Methods and research (pp. 211-215). New York: Appleton-Century-Crofts.

DeFries, J.C. (1967). Effects of heredity and prenatal stress on behavior of offspring. Illinois Research, 9, 6-7.

DeFries, J.C., Thomas, E.A., Hegmann, J.P., & Weir, M.W. (1967). Open-field behavior in mice: Analysis of maternal effects by means of ovarian transplantation. Psychonomic Science, 8, 207-208.

DeFries, J.C., Weir, M.W., & Hegmann, J.P. (1967). Differential effects of prenatal maternal stress on offspring behavior in mice as a function of genotype and stress. Journal of Comparative and Physiological Psychology, 63, 332-334. Reprinted in T.E. McGill, Ed. (1973), Readings in animal behavior (2nd ed., pp. 211-213). New York: Holt, Rinehart and Winston.

McReynolds, W.E., Weir, M.W., & DeFries, J.C. (1967). Open-field behavior in mice: Effect of test illumination. Psychonomic Science, 9, 277-278.

Dixon, L.K., & DeFries, J.C. (1968). Development of open-field behavior in mice: Effects of age and experience. Developmental Psychobiology, 1, 100-107.

Dixon, L.K., & DeFries, J.C. (1968). Effects of illumination on open-field behavior in mice. Journal of Comparative and Physiological Psychology, 66, 803-805.

Hegmann, J.P., & DeFries, J.C. (1968). Open-field behavior in mice: Genetic analysis of repeated measures. Psychonomic Science, 13, 27-28.

DeFries, J.C. (1969). Pleiotropic effects of albinism on open-field behavior in mice. Nature, 221, 65-66.

DeFries, J.C., Hegmann, J.P., Ross, D.B., & Howard, M.K. (1969). A quantitative genetic analysis of change in open-field behavior of mice. Psychonomic Science, 17, 153-154.

DeFries, J.C., & McClearn, G.E. (1970). Social dominance and Darwinian fitness in the laboratory mouse. American Naturalist, 104, 408-411.

DeFries, J.C., Wilson, J.R., & McClearn, G.E. (1970). Open-field behavior in mice: Selection response and situational generality. Behavior Genetics, 1, 195-211.

Hegmann, J.P., & DeFries, J.C. (1970). Are genetic correlations and environmental correlations correlated? Nature, 226, 284-286.

Hegmann, J.P., & DeFries, J.C. (1970). Maximum variance linear combinations from phenotypic, genetic, and environmental covariance matrices. Multivariate Behavioral Research, 5, 9-18.

Klein, T.W., & DeFries, J.C. (1970). Similar polymorphisms of taste sensitivity to PTC in mice and men. Nature, 225, 555-557.

Klein, T.W., & DeFries, J.C. (1970). Taste sensitivity in infrahuman species: Use of a genetic model to test the validity of alternative measures. Behavior Research Methods and Instrumentation, 2, 106-107.

Klein, T.W., Howard, J., & DeFries, J.C. (1970). Agonistic behavior in mice: Strain differences as a function of test illumination. Psychonomic Science, 19, 177-178.

Vandenberg, S.G., & DeFries, J.C. (1970). Our hopes for Behavior Genetics. Behavior Genetics, 1, 1-2.

Whitney, G., McClearn, G.E., & DeFries, J.C. (1970). Heritability of alcohol preference in laboratory mice and rats. Journal of Heredity, 61, 165-169.

Klein, T.W., & DeFries, J.C. (1973). Racial and cultural differences in sensitivity to flickering light. Social Biology, 20, 212-217.

Klein, T.W., DeFries, J.C., & Finkbeiner, C.T. (1973). Heritability and genetic correlation: Standard errors of estimates and sample size. Behavior Genetics, 3, 355-364.

DeFries, J.C., Hegmann, J.P., & Halcomb, R.A. (1974). Response to 20 generations of selection for open-field activity in mice. Behavioral Biology, 11, 481-495.

DeFries, J.C., Vandenberg, S.G., McClearn, G.E., Kuse, A.R., Wilson, J.R., Ashton, G.C., & Johnson, R.C. (1974). Near identity of cognitive structure in two ethnic groups. Science, 183, 338-339.

Padeh, B., Wahlsten, D., & DeFries, J.C. (1974). Operant discrimination learning and operant bar-pressing rates in inbred and heterogeneous laboratory mice. Behavior Genetics, 4, 383-393.

Halcomb, R.A., Hegmann, J.P., & DeFries, J.C. (1975). Open-field behavior in mice: A diallel analysis of selected lines. Behavior Genetics, 5, 217-231.

Wilson, J.R., DeFries, J.C., McClearn, G.E., Vandenberg, S.G., Johnson, R.C., & Rashad, M.N. (1975). Cognitive abilities: Use of family data as a control to assess sex and age differences in two ethnic groups. International Journal of Aging and Human Development, 6, 261-276.

Deckard, B.S., Lieff, B., Schlesinger, K., & DeFries, J.C. (1976). Developmental patterns of seizure susceptibility in inbred strains of mice. Developmental Psychobiology, 9, 17-24.

DeFries, J.C., Ashton, G.C., Johnson, R.C., Kuse, A.R., McClearn, G.E., Mi, M.P., Rashad, M.N., Vandenberg, S.G., & Wilson, J.R. (1976). Parent-offspring resemblance for specific cognitive abilities in two ethnic groups. Nature, 261, 131-133.

DeFries, J.C., Vandenberg, S.G., & McClearn, G.E. (1976). Genetics of specific cognitive abilities. Annual Review of Genetics, 10, 179-207.

Johnson, R.C., DeFries, J.C., Wilson, J.R., McClearn, G.E., Vandenberg, S.G., Ashton, G.C., Mi, M.P., & Rashad, M.N. (1976). Assortative marriage for specific cognitive abilities in two ethnic groups. Human Biology, 48, 343-352.

Johnson, R.C., Park, J., DeFries, J.C., McClearn, G.E., Mi, M.P., Rashad, M.N., Vandenberg, S.G., & Wilson, J.R. (1976). Assortative marriage for specific cognitive abilities in Korea. Social Biology, 23, 311-316.

Kuse, A.R., & DeFries, J.C. (1976). Social dominance and Darwinian fitness in laboratory mice: An alternative test. Behavioral Biology, 16, 113-116.

Plomin, R., & DeFries, J.C. (1976). Letter in response to "The Heritability Hang-up," by M. Feldman & R.C. Lewontin. Science, 194, 10-12.

Foch, T.T., DeFries, J.C., McClearn, G.E., & Singer, S.M. (1977). Familial patterns of impairment in reading disability. Journal of Educational Psychology, 69, 316-329.

Gervais, M.C., DeFries, J.C., & Kuse, A.R. (1977). Open-field behavior in mice: Effect of litter size. Behavioral Biology, 20, 519-522.

Hewitt, J.K., Fulker, D.W., & DeFries, J.C. (1977). Open-field behavior in mice: Generality of results from a diallel analysis of replicate selected lines. Behavior Genetics, 7, 441-446.

Plomin, R., DeFries, J.C., & Loehlin, J.C. (1977). Genotype-environment interaction and correlation in the analysis of human behavior. Psychological Bulletin, 84, 309-322.

Plomin, R., DeFries, J. ., & Roberts, M.K. (1977). Assortative mating by unwed biological parents of adopted children. Science, 196, 449-450.

Crawford, C.B., & DeFries, J.C. (1978). Factor analysis of genetic and environmental correlation matrices. Multivariate Behavioral Research, 13, 297-318.

DeFries, J.C. (1978). "Heritability estimates" from family data. Behavior Genetics, 8, 481-482.

DeFries, J.C., Ashton, G.C., Johnson, R.C., Kuse, A.R., McClearn, G.E., Mi, M.P., Rashad, M.N., Vandenberg, S.G., & Wilson, J. . (1978). The Hawaii family study of cognition: A reply. Behavior Genetics, 8, 281-288.

DeFries, J.C., Gervais, M.C., & Thomas, E.A . (1978). Response to 30 generations of selection for open-field activity in laboratory mice. Behavior Genetics, 8, 3-13.

DeFries, J.C. & Plomin, R. (1978). Behavioral genetics. Annual Review of Psychology, 29, 473-515.

DeFries, J.C., Singer, S.M., Foch, T.T., & Lewitter, F.I. (1978). Familial nature of reading disability. British Journal of Psychiatry, 132, 361-367.

Park, J., Johnson, R.C., DeFries, J.C., McClearn, G.E., Mi, M.P., Rashad, M.N., Vandenberg, S.G., & Wilson, J.R. (1978). Parent-offspring resemblance for specific cognitive abilities in Korea. Behavior Genetics, 8, 43-52.

DeFries, J.C., Johnson, R.C., Kuse, A.R., McClearn, G.E., Polovina, J., Vandenberg, S.G., & Wilson, J.C. (1979). Familial resemblance for specific cognitive abilities. Behavior Genetics, 9, 23-43.

Ho, H-Z., Plomin, R., & DeFries, J.C. (1979). Selective placement in adoption. Social Biology, 26, 1-6.

Plomin, R., & DeFries, J.C. (1979). Multivariate behavioral genetic analysis of twin data on scholastic abilities. Behavior Genetics, 9, 505- 517.

Corley, R.P., DeFries, J.C., Kuse, A.R., & Vandenberg, S.G. (1980). Familial resemblance for the Identical Blocks test of spatial ability: No evidence for X-linkage. Behavior Genetics, 10, 211-215.

Decker, S.N., & DeFries, J.C. (1980). Cognitive abilities in families with reading disabled children. Journal of Learning Disabilities, 13, 517-522.

George, F.R., O'Connor, M.F., DeFries, J.C., & Collins, A.C. (1980). Components of the GABA system in mice selectively bred for differences in open-field activity. Brain Research, 200, 85-92.

Lewitter, F.I., DeFries, J.C., & Elston, R.C. (1980). Genetic models of reading disability. Behavior Genetics, 10, 9-30.

Plomin, R., & DeFries, J.C. (1980). Genetics and intelligence: Recent data. Intelligence, 4, 15-24.

Decker, S. N., & DeFries, J. C. (1981). Cognitive ability profiles in families of reading-disabled children.Developmental Medicine and Child Neurology, 23, 217-227.

DeFries, J.C., Plomin, R., Vandenberg, S.G., & Kuse, A.R. (1981). Parent-offspring resemblance for cognitive abilities in the Colorado Adoption Project: Biological, adoptive, and control parents and one-year-old children. Intelligence, 5, 245-277.

Hardy-Brown, K., Plomin, R., & DeFries, J.C. (1981). Genetic and environmental influences on the rate of communicative development in the first year of life. Developmental Psychology, 17, 704-717.

DeFries, J.C., Corley, R.P., Johnson, R.C., Vandenberg, S.G., & Wilson, J.R. (1982). Sex-by-generation and ethnic group-by-generation interactions in the Hawaii family study of cognition. Behavior Genetics, 12, 223-230.

Whitney, G., McClearn, G.E., & DeFries, J.C. (1982). Heritability of alcohol preference in laboratory mice and rats: Erroneous estimates. Behavior Genetics, 12, 543-546.

Baker, L.A., DeFries, J.C., & Fulker, D.W. (1983). Longitudinal stability of cognitive ability in the Colorado Adoption Project. Child Development, 54, 290-297.

DeFries, J.C., & Baker, L.A. (1983). Colorado Family Reading Study: Longitudinal analyses. Annals of Dyslexia, 33, 153-162.

DeFries, J.C., & Baker, L.A. (1983). Parental contributions to longitudinal stability in the Colorado Family Reading Study. Child Development, 54, 388-395.

Fulker, D.W., & DeFries, J.C. (1983). Genetic and environmental transmission in the Colorado Adoption Project: Path analysis. British Journal of Mathematical and Statistical Psychology, 36, 175-188.

Johnson, R., Nagoshi, C.T., Ahern, F.M., Wilson, J.R., DeFries, J.C., McClearn, G.E., & Vandenberg, S.G. (1983). Family background, cognitive ability, and personality as predictors of educational and occupational attainment. Social Biology, 30, 86-100.

Plomin, R., & DeFries, J.C. (1983). The Colorado Adoption Project. Child Development, 54, 276-289.

Vogler, G.P., & DeFries, J.C. (1983). Linearity of offspring-parent regression for general cognitive ability. Behavior Genetics, 13, 355-360.

Baker, L.A., Decker, S.N., & DeFries, J.C. (1984). Cognitive abilities in reading-disabled children: A longitudinal study. The Journal of Child Psychology and Psychiatry and Allied Disciplines, 25, 111-117.

Nagoshi, C.T., Johnson, R.C., DeFries, J.C., Wilson, J.R., & Vandenberg, S.G. (1984). Group differences and first principal component loadings in the Hawaii Family Study of Cognition: A test of the generality of "Spearman's hypothesis." Personality and Individual Differences, 5, 751-753.

Rice, T., Plomin, R., & DeFries, J.C. (1984). Development of hand preference in the Colorado Adoption Project. Perceptual and Motor Skills, 58, 683-689.

Vogler, G.P., DeFries, J.C., & Decker, S.N. (1984). Family history as an indicator of risk for reading disability. Journal of Learning Disabilities, 17, 616-618. (Reprinted in Journal of Learning Disabilities, 1985, 18, 419-421.)

Wilson, J.R., Erwin, V.G., DeFries, J.C., Petersen, D.R., & Cole-Harding, S. (1984). Ethanol dependence in mice: Direct and correlated responses to ten generations of selective breeding. Behavior Genetics, 14, 235-256.

Bennett, B., Fulker, D.W., & DeFries, J.C. (1985). Familial resemblance for general cognitive ability in the Hawaii Family Study of Cognition. Behavior Genetics, 15, 401-406.

DeFries, J.C., & Fulker, D.W. (1985). Multiple regression analysis of twin data. Behavior Genetics, 15, 467-473.

LaBuda, M.C., Vogler, G.P., DeFries, J.C., & Fulker, D.W. (1985). Multivariate familial analysis of cognitive measures in the Colorado Family Reading Study. Multivariate Behavioral Research, 20, 357-368.

Plomin, R., & DeFries, J.C. (1985). A parent-offspring adoption study of cognitive abilities in early childhood. Intelligence, 9, 341-356.

Plomin, R., Loehlin, J.C., & DeFries, J.C. (1985). Genetic and environmental components of "environmental" influences. Developmental Psychology, 21, 391-402.

Thompson, L.A., Plomin, R., & DeFries, J.C. (1985). Parent-infant resemblance for general and specific cognitive abilities in the Colorado Adoption Project. Intelligence, 9, 1-13.

Vogler, G.P., & DeFries, J.C. (1985). Bivariate path analysis of familial resemblance for reading ability and symbol processing speed. Behavior Genetics, 15, 111-121.

DeFries, J.C., & Fulker, D.W. (1986). Multivariate behavioral genetics and development. Behavior Genetics, 16, 1-10.

LaBuda, M.C., DeFries, J.C., & Fulker, D.W. (1986). Multiple regression analysis of twin data obtained from selected samples. Genetic Epidemiology, 3, 425-433.

LaBuda, M.C., DeFries, J.C., Plomin, R., & Fulker, D.W. (1986). Longitudinal stability of cognitive ability from infancy to early childhood: Genetic and environmental etiologies. Child Development, 57, 1142-1150.

Rice, T., Fulker, D.W., & DeFries, J.C. (1986). Multivariate path analysis of specific cognitive abilities in the Colorado Adoption Project. Behavior Genetics, 16, 107-125.

Thompson, L.A., Fulker, D.W., DeFries, J.C., & Plomin, R. (1986). Multivariate genetic analysis of "environmental" influences on infant cognitive development. British Journal of Developmental Psychology, 4, 347-353.

Vogler, G.P., & DeFries, J.C. (1986). Multivariate path analysis of cognitive ability measures in reading-disabled and control nuclear families and twins. Behavior Genetics, 16, 89-106.

DeFries, J.C., Fulker, D.W., & LaBuda, M.C. (1987). Evidence for a genetic aetiology in reading disability of twins. Nature, 329, 537-539.

DeFries, J.C., Plomin, R., & LaBuda, M.C. (1987). Genetic stability of cognitive development from childhood to adulthood. Developmental Psychology, 23, 4-12.

LaBuda, M.C., DeFries, J.C., & Fulker, D.W. (1987). Genetic and environmental covariance structures among WISC-R subtests: A twin study. Intelligence, 11, 233-244.

Loehlin, J.C., & DeFries, J.C. (1987). Genotype-environment correlation and IQ. Behavior Genetics, 17, 263-277.

Zieleniewski, A.M., Fulker, D.W., DeFries, J.C., & LaBuda, M.C. (1987). Multiple regression analysis of twin and sibling data. Personality and Individual Differences, 8, 787-791.

Bergeman, C.S., Plomin, R., DeFries, J.C., & Fulker, D.W. (1988). Path analysis of general and specific cognitive abilities in the Colorado Adoption Project: Early childhood. Personality and Individual Differences, 9, 391-395.

DeFries, J.C. (1988). Colorado Reading Project: Longitudinal analyses. Annals of Dyslexia, 38, 120-130.

DeFries, J.C., & Fulker, D.W. (1988). Multiple regression analysis of twin data: Etiology of deviant scores versus individual differences. Acta Geneticae Medicae et Gemellologiae: Twin Research, 37, 205-216.

Fulker, D.W., DeFries, J.C., & Plomin, R. (1988). Genetic influence on general mental ability increases between infancy and middle childhood. Nature, 336, 767-769.

LaBuda, M.C., & DeFries, J.C. (1988). Cognitive abilities in children with reading disabilities and controls: A follow-up study. Journal of Learning Disabilities, 21, 562-566.

LaBuda, M.C., & DeFries, J.C. (1988). Genetic and environmental etiologies of reading disability: A twin study. Annals of Dyslexia, 38, 131-138.

Rice, T., Fulker, D.W., DeFries, J.C., & Plomin, R. (1988). Path analysis of IQ during infancy and early childhood and an index of the home environment in the Colorado Adoption Project. Intelligence, 12, 27-45.

Thompson, L.A., Fulker, D.W., DeFries, J.C., & Plomin, R. (1988). Multivariate analysis of cognitive and temperament measures in 24-month-old adoptive and nonadoptive sibling pairs. Personality and Individual Differences, 9, 95-100.

Cyphers, L.H., Fulker, D.W., Plomin, R., & DeFries, J.C. (1989). Cognitive abilities in the early school years: No effects of shared environment between parents and offspring. Intelligence, 13, 369-386.

Decker, S.N., Vogler, G.P., & DeFries, J.C. (1989). Validity of self-reported reading disability by parents of reading-disabled and control children. Reading and Writing: An Interdisciplinary Journal, 1, 327-331.

DeFries, J.C. (1989). Gender ratios in children with reading disability and their affected relatives: A commentary. Journal of Learning Disabilities, 22, 544-555.

DeFries, J.C., Wilson, J.R., Erwin, V.G., & Petersen, D.R. (1989). LSXSS recombinant inbred strains of mice: Initial characterization. Alcoholism: Clinical and Experimental Research, 13, 196-200.

Gillis, J.J., & DeFries, J.C. (1989). Validity of school history as a diagnostic criterion for reading disability. Reading and Writing: An Interdisciplinary Journal, 1, 93-101.

LaBuda, M.C., & DeFries, J.C. (1989). Differential prognosis of reading-disabled children as a function of gender, socioeconomic status, IQ, and severity: A longitudinal study. Reading and Writing: An Interdisciplinary Journal, 1, 25-36.

Rice, T., Carey, G., Fulker, D.W., & DeFries, J.C. (1989). Multivariate path analysis of specific cognitive abilities in the Colorado Adoption Project: Conditional path model of assortative mating. Behavior Genetics, 19, 195-207.

Vogler, G.P., Baker, L.A., Decker, S.N., DeFries, J.C., & Huizinga, D.H. (1989). Cluster analytic classification of reading disability subtypes. Reading and Writing: An Interdisciplinary Journal, 1, 163-177.

Wadsworth, S.J., Gillis, J.J., DeFries, J.C., & Fulker, D.W. (1989). Differential genetic aetiology of reading disability as a function of age. The Irish Journal of Psychology, 10, 509-520.

Brooks, A., Fulker, D.W., & DeFries, J.C. (1990). Reading performance and general cognitive ability: A multivariate genetic analysis of twin data. Personality and Individual Differences, 11, 141-146.

Cardon, L.R., DiLalla, L.F., Plomin, R., DeFries, J.C., & Fulker, D.W. (1990). Genetic correlations between reading performance and IQ in the Colorado Adoption Project. Intelligence, 14, 245-257.

Coon, H., Fulker, D.W., DeFries, J.C., & Plomin, R. (1990). Home environment and cognitive ability of 7-year-old children in the Colorado Adoption Project: Genetic and environmental etiologies. Developmental Psychology, 26, 459-468.

DeFries, J.C., Wadsworth, S.J., & Gillis, J.J. (1990). Gender differences in cognitive abilities of reading-disabled twins. Annals of Dyslexia, 40, 216-228.

LaBuda, M.C., DeFries, J.C., & Pennington, B.F. (1990). Reading disability: A model for the genetic analysis of complex behavioral disorders. Journal of Counseling and Development, 68, 645-651.

Plomin, R., Corley, R., DeFries, J.C., & Fulker, D.W. (1990). Individual differences in television viewing in early childhood: Nature as well as nurture. Psychological Science, 1, 371-377.

DeFries, J.C., Olson, R.K., Pennington, B.F., & Smith, S.D. (1991). Colorado Reading Project: Past, present, and future. Learning Disabilities: A Multidisciplinary Journal, 2, 37-46.

DeFries, J.C., Stevenson, J., Gillis, J.J., & Wadsworth, S.J. (1991). Genetic etiology of spelling deficits in the Colorado and London twin studies of reading disability. Reading and Writing: An Interdisciplinary Journal, 3, 271-283. [Reprinted in B. F. Pennington (Ed.), Reading disabilities: Genetic and neurological influences (pp. 83-95). Dordrecht, The Netherlands: Kluwer Academic Publishers.]

Fulker, D.W., Cardon, L.R., DeFries, J.C., Kimberling, W.J., Pennington, B.F., & Smith, S.D. (1991). Multiple regression analysis of sib-pair data on reading to detect quantitative trait loci. Reading and Writing: An Interdisciplinary Journal, 3, 299-313. [Reprinted in B.F. Pennington (Ed.), Reading disabilities: Genetic and neurological influences (pp. 111-125). Dordrecht, The Netherlands: Kluwer Academic Publishers.]

Gilger, J.W., Pennington, B.F., & DeFries, J.C. (1991). Risk for reading disability as a function of parental history in three family studies. Reading and Writing: An Interdisciplinary Journal, 3, 205-217. [Reprinted in B.F. Pennington (Ed.), Reading disabilities: Genetic and neurological influences (pp. 17-29). Dordrecht, The Netherlands: Kluwer Academic Publishers.]

Olson, R.K., Gillis, J.J., Rack, J.P., DeFries, J.C., & Fulker, D.W. (1991). Confirmatory factor analysis of word recognition and process measures in the Colorado Reading Project. Reading and Writing: An Interdisciplinary Journal, 3, 235-248. [Reprinted in B.F. Pennington (Ed.), Reading disabilities: Genetic and neurological influences (pp. 47-60). Dordrecht, The Netherlands: Kluwer Academic Publishers.]

Pennington, B.F., Gilger, J.W., Pauls, D., Smith, S.A., Smith, S.D., & DeFries, J.C. (1991). Evidence for major gene transmission of developmental dyslexia. Journal of the American Medical Association, 266, 1527-1534.

Plomin, R., Coon, H., Carey, G., DeFries, J.C., & Fulker, D.W. (1991). Parent-offspring and sibling adoption analyses of parental ratings of temperament in infancy and childhood. Journal of Personality, 59, 705-732.

Braungart, J.M., Plomin, R., DeFries, J.C., & Fulker, D.W. (1992). Genetic influence on tester-rated infant temperament as assessed by Bayley's Infant Behavior Record: Nonadoptive and adoptive siblings and twins. Developmental Psychology, 28, 40-47.

Cardon, L.R., Corley, R.P., DeFries, J.C., Plomin, R., & Fulker, D.W. (1992). Factorial validation of a telephone test battery of specific cognitive abilities. Personality and Individual Differences, 13, 1047-1050.

Cardon, L.R., Fulker, D.W., DeFries, J.C., & Plomin, R. (1992). Continuity and change in general cognitive ability from 1 to 7 years of age. Developmental Psychology, 28, 64-73.

Cardon, L.R., Fulker, D.W., DeFries, J.C., & Plomin, R. (1992). Multivariate genetic analysis of specific cognitive abilities in the Colorado Adoption Project at Age 7. Intelligence, 16, 383-400.

Cherny, S.S., Cardon, L.R., Fulker, D.W., & DeFries, J.C. (1992). Differential heritability across levels of cognitive ability. Behavior Genetics, 22, 153-162.

Cherny, S.S., DeFries, J.C., & Fulker, D.W. (1992). Multiple regression analysis of twin data: A model-fitting approach. Behavior Genetics, 22, 489-497.

Emde, R.N., Plomin, R., Robinson, J., Corley, R., DeFries, J., Fulker, D.W., Reznick, J.S., Campos, J., Kagan, J., & Zahn-Waxler, C. (1992). Temperament, emotion, and cognition at fourteen months: The MacArthur Longitudinal Twin Study. Child Development, 63, 1437-1455.

Gilger, J.W., Pennington, B.F., & DeFries, J.C. (1992). A twin study of the etiology of comorbidity: Attention-deficit hyperactivity disorder and dyslexia. Journal of the American Academy of Child and Adolescent Psychiatry, 31, 343-348.

Gillis, J.J., DeFries, J.C., & Fulker, D.W. (1992). Confirmatory factor analysis of reading and mathematics performance: A twin study. Acta Geneticae Medicae et Gemellologiae, 41, 287-300.

Gillis, J.J., Gilger, J.W., Pennington, B.F., & DeFries, J.C. (1992). Attention-deficit disorder in reading-disabled twins: Evidence for a genetic etiology. Journal of Abnormal Child Psychology, 20, 303-315.

Johnson, T.E., DeFries, J.C., & Markel, P.D. (1992). Mapping quantitative trait loci for behavioral traits in the mouse. Behavior Genetics, 22, 635-653.

Pennington, B.F., Gilger, J.W., Olson, R.K., & DeFries, J.C. (1992). The external validity of age- versus IQ-discrepancy definitions of reading disability: Lessons from a twin study. Journal of Learning Disabilities, 25, 562-573.

Wadsworth, S.J., DeFries, J.C., Stevenson, J., Gilger, J.W., & Pennington, B.F. (1992). Gender ratios among reading-disabled children and their siblings as a function of parental impairment. Journal of Child Psychology and Psychiatry, 33, 1229-1239.

Waldman, I.D., DeFries, J.C., & Fulker, D.W. (1992). Quantitative genetic analysis of IQ development in young children: Multivariate multiple regression with orthogonal polynomials. Behavior Genetics, 22, 229-238.

Coon, H., Carey, G., Fulker, D.W., & DeFries, J.C. (1993). Influences of school environment on the academic achievement scores of adopted and nonadopted children. Intelligence, 17, 79-104.

Mitton, J.B., Schuster, W.S.F., Cothran, E.G., & DeFries, J.C. (1993). Correlation between the individual heterozygosity of parents and their offspring. Heredity, 71, 59-63.

Plomin, R., Emde, R.N., Braungart, J.M., Campos, J., Corley, R., Fulker, D.W., Kagan, J., Reznick, J.S., Robinson, J., Zahn-Waxler, C., & DeFries, J.C. (1993). Genetic change and continuity from 14 to 20 months: The MacArthur Longitudinal Twin Study. Child Development, 64, 1354-1376.

Stevenson, J., Pennington, B.F., Gilger, J.W., DeFries, J.C., & Gillis, J.J. (1993). Hyperactivity and spelling disability: Testing for shared genetic aetiology. Journal of Child Psychology and Psychiatry, 34, 1137-1152.

Wadsworth, S.J., DeFries, J.C., & Fulker, D.W. (1993). Cognitive abilities of children at 7 and 12 years of age in the Colorado Adoption Project. Journal of Learning Disabilities, 26, 611-615.

Alarcón, M., DeFries, J.C., & Gillis, J.J. (1994). Familial resemblance for measures of reading performance in families of reading-disabled and control twins. Reading and Writing: An Interdisciplinary Journal, 6, 93-101.

Cardon, L.R., Smith, S.D., Fulker, D.W., Kimberling, W.J., Pennington, B.F., & DeFries, J.C. (1994). Quantitative trait locus for reading disability on chromosome 6. Science, 266, 276-279.

Cherny, S.S., Fulker, D.W., Corley, R.P., Plomin, R., & DeFries, J.C. (1994). Continuity and change in infant shyness from 14 to 20 months. Behavior Genetics, 24, 365-379.

Cherny, S.S., Fulker, D.W., Emde, R.N., Robinson, J., Corley, R.P., Reznick, J.S., Plomin, R., & DeFries, J.C. (1994). A developmental-genetic analysis of continuity and change in the Bayley Mental Development index from 14 to 24 months: The MacArthur Longitudinal Twin Study. Psychological Science, 5, 354-360.

Gilger, J.W., Borecki, I.B., DeFries, J.C., & Pennington, B.F. (1994). Commingling and segregation analysis of reading performance in families of normal reading probands. Behavior Genetics, 24, 345-355.

Smolen, A., Marks, M.J., DeFries, J.C., & Henderson, N.D. (1994). Individual differences in sensitivity to nicotine in mice: Response to six generations of selective breeding. Pharmacology Biochemistry and Behavior, 49, 531-540.

Alarcón, M., DeFries, J.C., Fulker, D.W. (1995). Etiology of individual differences in reading performance: A test of sex-limitation. Behavior Genetics, 25, 17-23.

Braungart-Rieker, J., Rende, R.D., Plomin, R., DeFries, J.C., & Fulker, D.W. (1995). Genetic mediation of longitudinal associations between family environment and childhood behavior problems. Development and Psychopathology, 7, 233-245.

Casto, S.D., DeFries, J.C., & Fulker, D.W. (1995). Multivariate genetic analysis of Wechsler Intelligence Scale for Children-Revised (WISC-R) factors. Behavior Genetics, 25, 25-32.

Flint, J., Corley, R., DeFries, J.C., Fulker, D.W., Gray, J.A., Miller, S., & Collins, A.C. (1995). A simple genetic basis for a complex psychological trait in laboratory mice. Science, 269, 1432-1435.

Light, J.G., & DeFries, J.C. (1995). Comorbidity of reading and mathematics disabilities: Genetic and environmental etiologies. Journal of Learning Disabilities, 28, 96-106.

Light, J.G., Pennington, B.F., Gilger, J.W., & DeFries, J.C. (1995). Reading disability and hyperactivity disorder: Evidence for a common genetic etiology. Developmental Neuropsychology, 11, 323-335.

Markel, P.D., DeFries, J.C., & Johnson, T.E. (1995). Ethanol-induced anesthesia in inbred strains of long-sleep and short-sleep mice: A genetic analysis of repeated measures using censored data. Behavior Genetics, 25, 67-73.

Markel, P.D., DeFries, J.C., & Johnson, T.E. (1995). Use of repeated-measures in an analysis of ethanol-induced loss of righting reflex in inbred long-sleep and short-sleep mice. Alcoholism: Clinical and Experimental Research, 19, 299-304.

Wadsworth, S.J., DeFries, J.C., Fulker, D.W., Olson, R.K., & Pennington, B.F. (1995). Reading performance and verbal short-term memory: A twin study of reciprocal causation. Intelligence, 20, 145-167.

Wadsworth, S.J., DeFries, J.C., Fulker, D.W., & Plomin, R. (1995). Cognitive ability and academic achievement in the Colorado Adoption Project: A multivariate genetic analysis of parent-offspring and sibling data. Behavior Genetics, 25, 1-15.

Wadsworth, S.J., DeFries, J.C., Fulker, D.W., & Plomin, R. (1995). Covariation among measures of cognitive ability and academic achievement in the Colorado Adoption Project: Sibling analysis. Personality and Individual Differences, 18, 63-73.

Casto, S.D., Pennington, B.F., Light, J.G., & DeFries, J.C. (1996). Differential genetic etiology of reading disability as a function of mathematics performance. Reading and Writing: An Interdisciplinary Journal, 8, 295-306.

DeFries, J.C., & Alarcón, M. (1996). Genetics of specific reading disability. Mental Retardation and Developmental Disabilities Research, 2, 39-47.

Knopik, V.S., DeFries, J.C., & Alarcón, M. (1996). Gender differences in cognitive abilities of opposite-sex and same-sex twin pairs with reading disability. Annals of Dyslexia, 46, 241-257.

Markel, P.D., Fulker, D.W., Bennett, B., Corley, R.P., DeFries, J.C., Erwin, V.G., & Johnson, T.E. (1996). Quantitative trait loci for ethanol sensitivity in the LSXSS recombinant inbred strains: Interval mapping. Behavior Genetics, 26, 447-458.

Saudino, K.J., Plomin, R., & DeFries, J.C. (1996). Tester-rated temperament at 14, 20, and 24 months: Environmental change and genetic continuity. British Journal of Developmental Psychology, 14, 129-144.

Schmitz, S., Saudino, K.J., Plomin, R., Fulker, D.W., & DeFries, J.C. (1996). Genetic and environmental influences on temperament in middle childhood: Analyses of teacher and tester ratings. Child Development, 67, 409-422.

Alarcón, M., & DeFries, J.C. (1997). Reading performance and general cognitive ability in twins with reading difficulties and control pairs. Personality and Individual Differences, 22, 793-803.

Alarcón, M., DeFries, J.C., Light, J.G., & Pennington, B.F. (1997). A twin study of mathematics disability. Journal of Learning Disabilities, 30, 617-623.

DeFries, J.C., Filipek, P.A., Fulker, D.W., Olson, R.K., Pennington, B.F., Smith, S.D., & Wise, B.W. (1997). Colorado Learning Disabilities Research Center. Learning Disabilities: A Multidisciplinary Journal, 8, 7-19.

Knopik, V.S., Alarcón, M., & DeFries, J.C. (1997). Comorbidity of mathematics and reading deficits: Evidence for a genetic etiology. Behavior Genetics, 27, 447-453.

Plomin, R., Fulker, D.W., Corley, R., & DeFries, J.C. (1997). Nature, nurture, and cognitive development from 1 to 16 years: A parent-offspring adoption study. Psychological Science, 8, 442-447.

Sherman, S.L., DeFries, J.C., Gottesman, I.I., Loehlin, J.C., Meyer, J.M., Pelias, M.Z., Rice, J., & Waldman, I. (1997). BEHAVIORAL GENETICS ‘97: ASHG STATEMENT. Recent developments in human behavioral genetics: Past accomplishments and future directions. American Journal of Human Genetics, 60, 1265-1275.

Wadsworth, S.J., Corley, R.P., DeFries, J.C., Fulker, D.W., Carey, G., & Plomin, R. (1997). Substance experimentation in the Colorado Adoption Project. Personality and Individual Differences, 23, 463-471.

Alarcón, M. Plomin, R., Fulker, D.W., Corley, R., & DeFries, J.C. (1998). Multivariate path analysis of specific cognitive abilities data at 12 years of age in the Colorado Adoption Project. Behavior Genetics, 28, 255-264.

Gilger, J.W., Pennington, B.F., Harbeck, R.J., DeFries, J.C., Kotzin, B., Green, P., & Smith, S. (1998). A twin and family study of the association between immune system dysfunction and dyslexia using blood serum immunoassay and survey data. Brain and Cognition, 36, 310-333.

Knopik, V.S., & DeFries, J.C. (1998). Common and specific gender influences on individual differences in reading performance: A twin study. Personality and Individual Differences, 25, 269-277.

Knopik, V.S., & DeFries, J.C. (1998). A twin study of gender-influenced individual differences in general cognitive ability. Intelligence, 26, 81-89.

Light, J.G., DeFries, J.C., & Olson, R.K. (1998). Multivariate behavioral genetic analysis of achievement and cognitive measures in reading-disabled and control twin pairs. Human Biology, 70, 215-237.

Plomin R., Corley, R., Caspi, A., Fulker, D.W., & DeFries, J.C. (1998). Adoption results for self-reported personality: Evidence for nonaddictive genetic effects? Journal of Personality and Social Psychology, 75, 211-218.

Plomin, R., & DeFries, J.C. (1998). The genetics of cognitive abilities and disabilities. Scientific American, 278, 62-69

Alarcón, M., Plomin, R., Fulker, D. W., Corley, R., DeFries, J.C. (1999). Molarity not modularity: Multivariate genetic analysis of specific cognitive abilities in parents and their 16-year-old children in the Colorado Adoption Project. Cognitive Development, 14, 175-193.

Gayán, J., Smith, S.D., Cherny, S.S., Cardon, L.R., Fulker, D.W., Brower, A.M., Olson, R.K., Pennington, B.F., & DeFries, J.C. (1999). Quantitative-trait locus for specific language and reading deficits on chromosome 6p. American Journal of Human Genetics, 64, 157-164.

Knopik, V.S., & DeFries, J.C., (1999). Etiology of covariation between reading and mathematics performance: a twin study. Twin Research, 2, 226-234.

Pennington, B.F., Filipek, P.A., Lefly, D., Churchwell, J., Kennedy, D.N., Simon, J.H., Filley, C.M., Galaburda, A., Alarcón, M., & DeFries, J.C. (1999). Brain morphometry in reading-disabled twins. Neurology, 53, 723-729.

Schmitz, S., Fulker, D.W., Plomin, R., Zahn-Waxler, C., Emde, R.N., & DeFries, J.C. (1999). Temperament and problem behaviour during early childhood. International Journal of Behavioral Development, 23, 333-355.

Wadsworth, S.J., Fulker, D.W., & DeFries, J.C. (1999). Stability of genetic and environmental influences on reading performance at 7 and 12 years of age in the Colorado Adoption Project. International Journal of Behavioral Development, 23, 319-332.

Alarcón, M., Knopik, V.S., & DeFries, J.C. (2000). Covariation of mathematics achievement and general cognitive ability in twins. Journal of School Psychology, 38, 63-77.

Alarcón, M., Pennington, B.F., Filipek, P.A., DeFries, J.C. (2000). Etiology of neuroanatomical correlates of reading disability. Developmental Neuropsychology, 17, 339-360.

Davis, C.J., Knopik, V.S., Wadsworth, S.J., & DeFries, J.C. (2000). Self-reported reading problems in parents of twins with reading difficulties. Twin Research 3, 88-91.

O’Connor, T.G., Caspi, A., DeFries, & J.C., Plomin, R. (2000). Are associations between parental divorce and children’s adjustment genetically mediated? An adoption study. Developmental Psychology, 6, 429-437.

Pennington, B.F., Filipek, P.A., Lefly, D., Chhabildas, N., Kennedy, D.N., Simon, J.H., Filley, C.M., Galaburda, A, & DeFries, J.C. (2000). A twin MRI study of size variations in the human brain. Journal of Cognitive Neuroscience, 12, 223-232.

Wadsworth, S.J., Knopik, V.S., & DeFries, J.C. (2000). Reading disability in boys and girls: No evidence for a differential genetic etiology. Reading and Writing: An Interdisciplinary Journal, 13, 133-145.

Wadsworth, S.J., Olson, R.K., Pennington, B.F., & DeFries, J.C. (2000). Differential genetic etiology of reading disability as a function of IQ. Journal of Learning Disabilities, 33, 192-199.

Willcutt, E.G., Pennington, B.F., & DeFries J.C. (2000). Etiology of inattention and hyperactivity/impulsivity in a community sample of twins with learning difficulties. Journal of Abnormal Child Psychology, 28, 149-159.

Willcutt, E.G., Pennington, B.F., & DeFries J.C. (2000). Twin study of the etiology of comorbidity between reading disability and attention-deficit/hyperactivity disorder. American Journal of Medical Genetics (Neuropsychiatric Genetics), 96, 293-301.

Compton, D.L., DeFries, J.C., Olson, R.K. (2001). Are RAN- and phonological awareness-deficits additive in children with reading disbilities? Dyslexia, 7, 125-149.
Davis, C.J., Gayán, J., Knopik, V.S., Smith, S.D., Cardon, L.R., Pennington, B.F., Olson, R.K., & DeFries, J.C. (2001). Etiology of reading difficulties and rapid naming: The Colorado Twin Study of Reading Disability. Behavior Genetic, 31, 625-635.

Davis, C.J., Knopik, V.S., Olson, R.K., Wadsworth, S.J., DeFries, J.C. (2001). Genetic and environmental influences on rapid naming and reading ability: A twin study. Annals of Dyslexia, 51, 231-247.

Turri, M.G., Datta, S.R., DeFries, J.C., Henderson, N.D., & Flint, J. (2001). QTL analysis identifies multiple behavioral dimensions in ethological tests of anxiety in laboratory mice. Current Biology, 11, 725-734.

Turri, M.G., Henderson, N.D., DeFries, J.C., & Flint, J. (2001). Quantitative trait locus mapping in laboratory mice derived from a replicated selection experiment for open-field activity. Genetics, 158, 1217-1226.

Wadsworth, S.J., Corley, R.P., Hewitt, J.K., & DeFries, J.C. (2001). Stability of genetic and environmental influences on reading performance at 7, 12, and 16 years of age in the Colorado Adoption Project. Behavior Genetics, 31, 353-359.

Compton, D.L., Olson, R.K., DeFries, J.C., & Pennington, B.F. (2002). Comparing the relationships among two different versions of alphanumeric rapid automatized naming and word level reading skills. Scientific Studies of Reading, 6(4), 343-368.

Fisher, S.E., & DeFries, J.C. (2002). Developmental Dyslexia: Genetic Dissection of a complex cognitive trait. Nature Reviews Neuroscience, 3, 767-780.

Fisher, S.E., Francks, C., Marlow, A.J., MacPhie, L., Newbery, D.F., Cardon, L.R., Ishikawa-Brush, Y., Richardson, A.J., Talcott, J.B., Gayán, J., Olson, R.K., Pennington, B.F., Smith, S.D., DeFries, J.C., Stein, J.F., & Monaco, A.P. (2002). Independent genome-wide scans identify a chromosome 18 quantitative-trait locus influencing dyslexia. Nature Genetics, 30, 86-91.

Francks, C., Fisher, S.E., Olson, R.K., Pennington, B.F., Smith, S.D., DeFries, J.C., & Monaco, A.P. (2002). Fine mapping of the chromosome 2p12-16 dyslexia susceptibility locus: quantitative association analysis and positional candidate genes SEMA4F and OTX1. Psychiatric Genetics, 12, 35-41.

Kaplan, D.E., Gayán, J., Ahn, J., Won, T.-W., Pauls, D., Olson, R.K., & DeFries, J.C. (2002). Evidence for linkage and association with reading disability, on 6p21.3-22. American Journal of Human Genetics, 70, 1287-1298.

Knopik, V.S., Smith S.D., Cardon, L., Pennington, B., Gayán, J., Olson, R.K., DeFries, J.C. (2002). Differential genetic etiology of reading component processes as a function of IQ. Behavior Genetics, 32, 181-198.

Wadsworth, S.J., Corley, R.P., Hewitt, J.K., Plomin, R., & DeFries, J.C. (2002). Parent–offspring resemblance for reading performance at 7, 12 and 16 years of age in the Colorado Adoption Project. Journal of Child Psychology and Psychiatry, 43(6), 769-774.

Willcutt, E,G., Pennington, B.F., Smith, S.D., Cardon, L.R., Gayán, J., Knopik, V.S., Olson, R.K., & DeFries, J.C. (2002). Quantitative trait locus for reading disability on chromosome 6p is pleiotropic for attention-deficit/hyperactivity disorder. American Journal of Human Genetics (Neuropsychiatric Genetics), 114, 260-268.

Young, S.E., Smolen A., Corley, R.P., Krauter, K.S., DeFries, J.C., Crowley, T.J., & Hewitt, J.K. (2002). Dopamine transporter polymorphism associated with externalizing behavior problems in children. American Journal of Human Genetics (Neuropsychiatric Genetics), 114, 144-149.

Bishop, E.G., Cherny, S.S., Corley, R., DeFries, J.C., & Hewitt, J.K. (2003). Developmental genetic analysis of general cognitive ability from 1 to 12 years in a sample of adoptees, biological siblings, and twins. Intelligence, 31, 31-49.

O’Connor, T.G., Caspi, A., DeFries, J.C., & Plomin, R. (2003). Genotype–environment interaction in children’s adjustment to parental separation. Journal of Child Psychology and Psychiatry, 44(6), 849-856.

Deffenbacher, K.E., Kenyon, J.B., Hoover, D.M., Olson, R.K., Pennington, B.F., DeFries, J.C., & Smith, S.D. (2004). Refinement of the 6p21.3 quantitative trait locus influencing dyslexia: Linkage and association analyses. Human Genetics, 115, 128-138.

Flint, J., DeFries, J.C., & Henderson, N.D. (2004). Little epistasis for anxiety-related measures in the DeFries strains of laboratory mice. Mammalian Genome: Genes and Phenotypes, 15, 77-82.

Francks, C., Paracchini, S., Smith, S.D., Richarson, A.J., Scerri, T.S., Cardon, L.R., Marlow, A.J., MacPhie, L., Walter, J., Pennington., B.F., Fisher, S.E., Olson, R.K., DeFries, J.C., Stein, J.F., Monaco, A.P. (2004). A 77-kilobase region of chromosome 6p22.2 is associated with dyslexia in families from the United Kingdom and from the United States. American Journal of Human Genetics, 75, 1046-1058.

Henderson, N.D., Turri, M.G., DeFries, J.C., & Flint, J. (2004). QTL analysis of multiple behavioral measures of anxiety in mice. Behavior Genetics, 34(3), 267-293.

Hulslander, J., Talcott, J., Witton, C., DeFries, J., Pennington, B., Wadsworth, S., Willcutt, E., Olson, R. (2004). Sensory processing, reading, IQ, and attention. Journal of Experimental Child Psychology, 88, 274-295.

Tiu, R.D., Wadsworth, S.J., Olson, R.K., & DeFries, J.C. (2004). Causal models of reading disability: A twin study. Twin Research, 7(3), 275-283.

Turri, M.G., DeFries, J.C., Henderson, N.D., & Flint, J. (2004). Multivariate analysis of quantitative trait loci influencing variation in anxiety-related behavior in laboratory mice. Mammalian Genome: From Genotype to Phenotype, 15, 69-76.

Williams, R.W., Bennett, B., Lu, L., Gu, J., DeFries, J.C., Carosone-Link, P.J., Rikke, B.A., Belknap, J.K., Johnson, T.E. (2004). Genetic structure of the LXS panel of recombinant inbred mouse strains: A powerful resource for complex trait analysis. Mammalian Genome, 15, 637-647.

Byrne, B., Wadsworth, S., Corley, R., Samuelsson, S., Quain, P., DeFries, J.C., Willcutt, E., & Olson, R.K. (2005). Longitudinal twin study of early literacy development: Preschool and kindergarten phases. Scientific Studies of Reading, 9(3), 219-235.

Gayán, J., Willcutt, E.G., Fisher, S.E., Francks, C., Cardon, L.R., Olson, R.K., Pennington, B.F., Smith, S.D., Monaco, A.P., and DeFries, J.C. (2005). Bivariate linkage scan for reading disability and attention-deficit/hyperativity disorder localizes pleiotropic loci. Journal of Child Psychology and Psychiatry, 46(10), 1045-1056.

Meng, H., Hager, K., Held, M., Page, G.P., Olson, R.K., Pennington, B.F., DeFries, J.C., Smith, S.D., Gruen, J.R. (2005). TDT-association analysis of EKN1 and dyslexia in a Colorado twin cohort. Human Genetics, 118, 87-90.

Meng, H., Smith, S.D., Hager, K., Held, M., Liu, J., Olson, R.K., Pennington, B.F., DeFries, J.C., Gelernter, J., O'Reilly-Pol, T., Somlo, S., Skudlarski, P., Shaywitz, S.E., Shaywitz, B.A., Marchione, K., Wang, Y., Paramasivam, M., LoTurco, J.J., Page, G.P., & Gruen J.R. (2005). DCDC2 is associated with reading disability and modulates neuronal development in the brain. Proceedings of the National Academy of Sciences, 102(47), 17053-17058.

Samuelsson, S., Byrne, B., Quain, P., Wadsworth, S., Corley, R., DeFries, J.C., Willcutt, E., & Olson, R. (2005). Environmental and genetic influences on prereading skills in Australia, Scandinavia, and the United States. Journal of Educational Psychology, 97(4), 705-722.

Wadsworth, S.J., & DeFries, J.C. (2005). Genetic etiology of reading difficulties in boys and girls. Twin Research and Human Genetics, 8(6), 594-601.

Bricker, J.B., Stallings, M.C., Corley, R.P., Wadsworth, S.J., Bryan, A., Timberlake, D.S., Hewitt, J.K., Caspi, A., Hofer, S.M., Rhea, S.A., DeFries, J.C. (2006).  Genetic and environmental influences on age at sexual initiation in the Colorado Adoption Project.  Behavior Genetics, 36, 820-832.

Byrne, B., Olson, R.K., Samuelsson, S., Wadsworth, S., Corley, R., DeFries, J.C., & Willcutt, E. (2006).  Genetic and environmental influences on early literacy.  Journal of Research in Reading, 29(1), 33-49.

Friedman, N.P., Miyake, A., Corley, R.P., Young, S.E., DeFries, J.C., & Hewitt, J.K. (2006).  Not all executive functions are related to intelligence.  Psychological Science, 17(2), 172-179.

Hawke, J.L., Wadsworth, S.J., & DeFries, J.C. (2006).  Genetic influences on reading difficulties in boys and girls: The Colorado Twin Study.  Dyslexia, 12, 21-29.

Keenan, J.M., Betjemann, R.S., Wadsworth, S.J., DeFries, J.C., & Olson, R.K. (2006).  Genetic and environmental influences on reading and listening comprehension.  Journal of Research in Reading, 29(1), 75-91.

Shanahan, M.A., Pennington, B.F., Yerys, B.E., Scott, A., Boada, R., Willcutt, E.G., Olson, R.K., & DeFries, J.C. (2006).  Processing speed deficits in attention deficit/hyperactivity disorder and reading disability.  Journal of Abnormal Child Psychology, 34, 585-602.

Astrom, R.L., Wadsworth, S.J., & DeFries, J.C. (2007).  Etiology of the stability of reading difficulties: The Longitudinal Twin Study of Reading Disabilities.  Twin Research and Human Genetics, 10(3), 434-439.

Bidwell, L.C., Willcutt, E.G., DeFries, J.C., Pennington, B.F. (2007). Testing for neuropsychological endophenotypes in siblings discordant for attention-deficit/hyperactivity disorder. Biological Psychiatry, 62, 991-998.

Byrne, B., Samuelsson, S., Wadsworth, S., Hulslander, J., Corley, R., DeFries, J.C., Quain, P., Willcutt, E.G., & Olson, R.K. (2007).  Longitudinal twin study of early literacy development: Preschool through  grade 1.  Reading and Writing, 20, 77-102.

Friend, A., DeFries, J.C., Wadsworth, S.J., & Olson, R.K. (2007).  Genetic and environmental influences on word recognition and spelling deficits as a function of age.  Behavior Genetics, 37, 477-486.

Hawke, J.L., Wadsworth, S.J., Olson, R.K., & DeFries, J.C. (2007).  Etiology of reading difficulties as a function of gender and severity.  Reading and Writing, 20, 13-25.

Samuelsson, S., Olson, R., Wadsworth, S., Corley, R., DeFries, J.C., Willcutt, E., Hulslander, J., Byrne, B. (2007).  Genetic and environmental influences on prereading skills and early reading and spelling development in the United States, Australia, and Scandinavia.  Reading and Writing, 20, 51-75.

Wadsworth, S.J., DeFries, J.C., Olson, R.K., & Willcutt, E.G. (2007). Colorado Longitudinal Twin Study of Reading Disability. Annals of Dyslexia, 57, 139-160.

Willcutt, E.G., Betjemann, R.S., Pennington, B.F., Olson, R.K., DeFries, J.C., & Wadsworth, S.J. (2007). Longitudinal Study of Reading Disability and Attention Deficit/Hyperactivity Disorder: Implications for education. Mind, Brain and Education, 1(4), 181-192.

Willcutt, E.G., Betjemann, R.S., Wadsworth, S.J., Samuelsson, S., Corley, R., DeFries, J.C., Byrne, B., Pennington, B.F., Olson, R.K. (2007).  Preschool twin study of the relation between attention-deficit/hyperactivity disorder and prereading skills.  Reading and Writing, 20, 103-125.

Willcutt, E.G., Pennington, B.F., Olson, R.K., & DeFries, J.C. (2007). Understanding cormorbidity: A twin study of reading disability and attention-deficit/hyperactivity disorder. American Journal of Medical Genetics Part B (Neuropsychiatric Genetics), 114B, 709-714.

Byrne, B., Coventry, W.L., Olson, R.K., Hulslander, J., Wadsworth, S., DeFries, J.C., Corley, R., Willcutt, E.G., & Samuelsson, S. (2008). A behaviour-genetic analysis of orthographic learning, spelling and decoding. Journal of Research in Reading, 31(1), 8-21.

Hawke, J.L., Stallings, M.C., Wadsworth, S.J., & DeFries, J.C. (2008). DeFries-Fulker and Pearson-Aitken model-fitting analyses of reading performance data from selected and unselected twin pairs. Behavior Genetics, 38, 101-107.

Rhee, S.H., Willcutt, E.G., Hartman, C.A., Pennington, B.F., DeFries, J.C. (2008). Test of alternative hypotheses explaining the comorbidity between Attention-Deficit/Hyperactivity Disorder and Conduct Disorder. Journal of Abnormal Child Psychology, 36, 29-40.