Intrafamilial correlations and heritability estimates for spatial ability in a minnesota sample

Data collected by university students on their family members showed intrafamilial correlations and heritability estimates for spatial ability similar in magnitude to those reported in three larger samples in Hawaii and Korea.This article is based on a paper presented at the Sixth Annual Meeting of the Behavior Genetics Association in Boulder. Colorado.     

Sex linkage and race differences in spatial ability: A reply

Stevens and Hyde have questioned only the empirical evidence relevant to Jensen's formulation of a genetic hypothesis to explain race and sex differences in spatial visualization ability, rather than the formulation of the hypothesisper se, which at present remains the only non-ad hoc hypothesis concerning these phenomena, which are admittedly in need of further empirical investigation. The formulation of potentially falsifiable hypotheses derived from genetic theory is the surest means for advancing knowledge in behavioral genetics.     

A comment on Jensen's note on sex linkage and race differences in spatial ability

Several criticisms of Jensen's hypothesis on sex linkage and race differences in spatial ability are raised. Data on whether blacks have a deficit in spatial ability are inconsistent. Whether there are X-linked influences on spatial ability has been questioned recently. Two studies provide data inconsistent with Jensen's hypothesis.     

Further evidence for a gene influencing spatial ability

Data for six spatial tests from 927 families of European ancestry, 369 families of Japanese ancestry, and 93 families of Chinese ancestry from the Hawaiian Family Study of Cognition were subjected to unified mixed-model segregation analysis. Father, mother, son, and daughter data sets from each ethnic group were separately age-adjusted and standardized and then separately subjected to transformation procedures to reduce skewness and kurtosis. Families were reassociated prior to segregation analysis. Evidence for a major gene contributing to spatial visualizing ability was obtained for Mental Rotations and Progressive Matrices even with a normalizing transformation which reduced skewness and kurtosis to zero. It was concluded that provision for testing deviation from Mendelian transmission in the unified model protected against false inference of a segregating major gene. Minimizing distributional differences in the components of a data set is an important pretreatment.The results reported here are made possible by the collaboration of a group of investigators (G. C. Ashton, R. C. Johnson, M.-P. Mi, and M. N. Rashad at the University of Hawaii and J. C. DeFries, G. E. McClearn, S. G. Vandenberg, and J. R. Wilson at the University of Colorado) supported by NSF Grant GB 34720 and National Institute of Child Health and Human Development Grant HD 06669. Support for I.B.B. was provided by NIMH Grant MH 14677.     

Familial resemblance for the Identical Blocks Test of spatial ability: No evidence for X linkage

The Identical Blocks Test of spatial ability was administered to subsamples of the two largest ethnic groups tested in the Hawaii Family Study of Cognition—Americans of European ancestry (171 families) and Americans of Japanese ancestry (98 families). Results of a hierarchical multiple regression analysis of family data and correlational analyses provided no evidence to support the hypothesis that spatial ability is influenced by a major, X-linked, recessive gene. Thus it appears that recent failures to replicate the sex-linkage pattern obtained by Stafford (1961) are not due to differences in the tests employed. We suggest that alternative explanations should be sought for the well-known sex difference in spatial ability.The results reported here are made possible by collaboration of a group of investigators (G. C. Ashton, R. C. Johnson, M. P. Mi, and M. N. Rashad at the University of Hawaii and J. C. DeFries, G. E. McClearn, S. G. Vandenberg, and J. R. Wilson at the University of Colorado) supported by NSF Grant GB-34720 and Grant HD-06669 from the National Institute of Child Health and Human Development. The senior author also acknowledges support by NIMH Grant MH-11167.     

Sex differences in spatial ability in children

There is considerable evidence that sex differences in spatial ability exist in adults, with males outperforming females at every age after puberty. It is difficult, however, to find sex differences in children younger than 13. This is due in part to the lack of adequate measures of spatial ability for use with children. We report the use of spatial tests for children that are similar to those that have shown large sex differences in adults and may be measuring ability comparable to adult spatial ability. Four tests of mental rotation and spatial visualization were given to two samples of children. The first sample consisted of 81 children (39 males and 42 females) aged 9 to 12 years. The second sample consisted of 42 children (21 males and 21 females) aged 9 to 13 years. Sex differences of .4–.6 standard deviations were found on three tests in both samples. These results indicate that sex differences in spatial ability can be found in preadolescents if appropriate tests are used. Measurement of these abilities in children facilitates the investigation of possible biological and sociocultural contributors to the sex differences in spatial ability.This study was supported by National Institutes of Health Grant HD19644 and NIH Biomedical Research Support Grant S07 RR05366-24.     

Genetic and environmental influences on the development of intelligence

Measures of intelligence were collected in 209 twin pairs at 5, 7, 10, and 12 years of age, as part of a longitudinal project on intelligence, brain function, and behavioral problems. Intelligence was measured at 5, 7, and 10 years of age with the RAKIT, a well-known Dutch intelligence test, consisting of 6 subscales. At 12 years of age, the complete WISC-R was administered (12 subscales). Both intelligence tests resulted in a measure of full-scale IQ (FSIQ). Participation rate is around 93% at age 12. Correlation coefficients over time are high: (r(5–7) = .65; r(5–10) = .65; r(5–12) = .64; r(7–10) = .72; r(7–12) = .69 and r(10–12) = .78). Genetic analyses show significant heritabilities at all ages, with the expected increase of genetic influences and decrease of shared environmental influences over the years. Genetic influences seem to be the main driving force behind continuity in general cognitive ability, represented by a common factor influencing FSIQ at all ages. Shared environmental influences are responsible for stability as well as change in the development of cognitive abilities, represented by a common factor influencing FSIQ at all ages and age-specific influences, respectively.     

Parent-offspring resemblance for specific cognitive abilities in Korea

Regressions of offspring on midparent value for tests of specific cognitive abilities in Korea were considerably higher than those for Americans of Japanese ancestry or Americans of European ancestry tested in Hawaii. This greater parent-offspring resemblance in Korea may be due to the particular method of test administration or to an increased genetic variance resulting from assortative mating. The pattern of parent-child correlations for three relatively pure tests of spatial ability and for the spatial factor did not conform to that of a sex-linked recessive character.The results reported here are made possible by collaboration of a group of investigators (G. C. Ashton, R. C. Johnson, M. P. Mi, and M. N. Rashad at the University of Hawaii, and J. C. DeFries, G. E. McClearn, S. G. Vandenberg, and J. R. Wilson at the University of Colorado) supported by NSF Grant GB-34720 and Grant HD-06669 from the National Institute of Child Health and Human Development.     

Genetic and environmental determinants of musical ability in twins

Analyses of musical ability data from the Loehlin and Nichols National Merit Scholarship study are presented. Musical ability is indexed by four measures: interest in a profession in music, performance in school, performance outside of school, and receiving honors in music. These variables pose a challenge for behavior genetic analysis since they do not conform to the assumptions of traditional linear models. For example, there is a dependent relationship between the honors and the performance variables; one cannot obtain honors without performance. Several methods were employed to deal with these relationships, and the following conclusions appeared regardless of the method used. First, twin correlations were always high, ranging from 0.44 to 0.90 in monozygotic (MZ) twins and from 0.34 to 0.83 in dizygotic (DZ) twins. Second, although there was evidence for heritable variation, the effects of common environment were almost always larger than the effects of heredity. Third, marital assortment was not of sufficient magnitude to account for these common environment effects. In the young adults in this sample, musical ability is influenced more by shared family environment than by shared genes.This research was supported in part by Grants HD-10333 and HD-18426 from the National Institute of Child Health and Human Development (NICHD). The paper was written while Hilary Coon was under the support of Training Grant HD-07289 from the NICHD. Preparation of the paper was facilitated by Grant RR-07013-20 awarded to the University of Colorado by the Biomedical Research Support Grant Program, Division of Research Resources, National Institutes of Health.     

Genetic regulation of melatonin excretion in urine

The melatonin excretion in urine was determined in 107 individuals from 23 nuclear families. Complex segregation analysis showed that the melatonin production might be regulated by an additive major gene.     

Cerebral lateralization and spatial ability

Frequencies of three cerebral dominance genotypes who show right or left ear superiority on a verbal dichotic listening test and left or right field superiority on a tachistoscopic lateral field test of perceptual dominance are deduced. A hypothesis is offered relating direction of cerebral dominance, as defined by genotype, to degree of lateral specialization and perceptual ability, and a theoretical distribution of subjects according to spatial-perceptual ability and lateralization is derived. This distribution corresponds almost exactly with empirical data, thus confirming the proposed correlation between lateralization and spatial-perceptual capacity.     

No evidence for sex-linked or sex-limited gene expression influencing spatial orientation

Scores of 83 pairs of twins and their parents on the Cubes Comparison Test have been analyzed to test competing hypotheses about the origin of individual differences in spatial orientation. Models allowing for polygenic sex-linked or sex-limited gene expression show no improvement in fit over the simple autosomal additive polygenic model. However, individual environmental influences (E ₁) account for twice as much variance in males as in females.     

Evidence for a major gene influencing performance on a vocabulary test

Scores on a vocabulary test given to members of 1818 nuclear families of different ethnic backgrounds were subjected to admixture analysis, segregation analysis utilizing both the mixed model and the transmission probability model and linkage analysis with 16 polymorphic markers. The data fitted a commingled distribution better than a unimodal distribution. Tests of the hypothesis that a major gene was segregating were not rejected by mixed model segregation analysis or by transmission probability analysis when provision was made for contribution from factors other than a major gene. There was no detectable heterogeneity by ethnic group nor by mating type. These analyses provide consistent support that there is a major gene for a component of verbal ability measured by a vocabulary test, and the segregation pattern is consistent with the expected Mendelian ratios. When vocabulary scores were adjusted for covariates including years of education, academic achievement, and reading habits, evidence for a major locus was lacking. The results of the linkage analysis were inconclusive. Current segregation models are affected by various factors leading to false inferences regarding monogenic mechanisms; however, in many respects, the mixed model and the transmission probability model are complementary with respect to power and robustness. The results of the analysis are discussed in this context.We thank Dr. J. M. Lalouel for access to his modified POINTER program, Professor N. E. Morton for access to NUCLEAR and POINTER, and Professor R. C. Elston for his support. The results reported here are made possible by collaboration of a group of investigators (G. C. Ashton, R. C. Johnson, M. P. Mi, and M. N. Rashad at the University of Hawaii and J. C. DeFries, G. E. McClearn, S. G. Vandenberg, and J. R. Wilson at the University of Colorado), supported by NSF Grant GB34720 and National Institute of Child Health and Human Development Grant HD06669.     

非特异性精神发育迟滞的遗传异质性

目的　探讨非特异性精神发育迟滞 (non- specific mental retardation,NSMR)的遗传方式。方法　采用分离分析法、Finney法和 Falconer法 ,对山东省遗传病群体调查中筛选出的 15 7个 NSMR家系进行了研究。结果　 U×U多发家庭接受常染色体隐性遗传 ;U× U总体属于常染色体隐性遗传 ,同时还有多基因的主基因效应 ,散发病例为 46 % ;U× A符合常染色体显性遗传 ,不完全外显。结论　 NSMR的遗传方式具有遗传异质性     

Segregation analysis of family data for 15 tests of cognitive ability

Segregation analysis of 15 tests of cognitive ability administered to 894 families of European ancestry and 366 families of Japanese ancestry gave evidence for a major gene contributing to performance on three tests of spatial ability in both ethnic groups. There was no evidence of major genes segregating in three other tests of spatial ability, or in tests measuring verbal ability, perceptual speed, or memory. The results supported the hypothesis that superior performance on ETS Hidden Patterns (HP) and Raven's Progressive Matrices (PM) is due in part to an autosomal dominant gene that accounts for 32% of the phenotypic variation in HP and 37% of the variation in PM. Evidence for a sex-limited autosomal dominant gene was found for a modification of the Shepard-Metzler Mental Rotations (MR) test, and 48% of the phenotypic variation in MR could be accounted for by this gene.The results reported here are made possible by collaboration of a group of investigators (G. C. Ashton, R. C. Johnson, M. P. Mi, and M. N. Rashad at the University of Hawaii, and J. C. DeFries, G. E. McClearn, S. G. Vandenberg, and J. R. Wilson at the University of Colorado) supported by NSF Grant GB 34720 and Grant HD 06669 from the National Institute of Child Health and Human Development.     

A study of X chromosome linkage with field dependence and spatial visualization

The purposes of this report are to describe a design for the study of X linkage, to illustrate its application using cognitive test scores, and to offer a linkage hypothesis suggested by these data. Sixty-seven three-son families were examined for two X chromosome marker variables—red-green color vision andXg(a) blood groups—and given a battery of cognitive tests of field dependence and spatial visualization abilities. Evidence was found to suggest that brothers who are identical inXg(a) phenotype are more similar to each other in extent of field dependence than brothers who are different inXg(a) phenotype. This result is tentative because of the small number of informative cases and the many linkage associations examined. If crossvalidated, such a finding would be consistent with the proposition that an X chromosome gene contributes to the field dependence-independence cognitive style.This study was partially supported by NIMH Grant No. 21989.     

Genetic and environmental influences on LDL subclass phenotypes

There is accumulating evidence that subclasses of low-density lipoproteins (LDL) are important in atherosclerosis. Several case-control studies have demonstrated that a predominance of small, dense LDL (LDL subclass phenotype B) is associated with increased risk of coronary heart disease (CHD). Phenotype B is also consistently characterized by an atherogenic lipoprotein phenotype, including increased levels of plasma triglyceride and decreased high-density lipoprotein cholesterol. Family studies and genetic linkage studies demonstrate that LDL subclasses are influenced by a single major gene effect, although this locus (or loci) remain to be definitively mapped. Twin studies confirm the presence of genetic effects, but also show that non-genetic influences are important. Hypolipidemic drugs, beta-blockers, diet and exercise, in particular, appear to influence the expression of LDL subclass phenotypes. This combination of genetic and environmental influences may provide opportunities to develop targeted intervention strategies to reduce CHD risk among genetically susceptible individuals.     

The independent prediction of general intelligence by elementary cognitive tasks: Genetic and environmental influences

Current theories of intelligence have, in some cases, begun to include elementary cognitive tasks. Behavioral genetic studies of intelligence have not taken these theories into account. The current study includes 135 MZ and 128 DZ twin pairs from the Western Reserve Twin Project. The 11 WISC-R subtests as well as 6 elementary cognitive tasks were employed. Using a Schmid-Leiman (1957) transformation, analyses indicate a four-group factor model, supported by a second-order general factor at both phenotypic and biometric levels. Results indicate that the general factor, group factors, and specific residuals are necessary when examining additive genetic variance. Common environmental variance can be collapsed into a single general factor.