Positive effects of paternal and maternal longevity on offspring’s lifespan are well established. However little is known about effects of parental longevity on the shape of offspring’s mortality trajectories. To address this problem, we studied familial transmission of human lifespan from parents to offspring using particularly reliable and complete data on European royal and noble families fo...

Reading is the processing of written language. Family resemblance for reading (dis)ability might be due to transmission of a genetic liability or due to family environment, including cultural transmission from parents to offspring. Familial-risk studies exploring neurobehavioral precursors for dyslexia and twin studies can only speak to some of these issues, but a combined twin-family study can...

Ataxia with vitamin E deficiency (AVED) is an autosomal recessive disease characterized clinically by neurological symptoms with often striking resemblance to those of Friedreich ataxia. This disorder has been reported previously as familial isolated vitamin E deficiency. We have mapped recently the AVED locus to a 5-cM confidence interval on chromosome 8q by homozygosity mapping in six Mediter...

Except for alcohol abuse, little is known about the familial aggregation for substance abuse. Here we report twin resemblance for non-alcohol substance use in the Washington University Twin Series, wherein probands were identified by consecutive admission to psychiatric facilities in the St. Louis area. A 5-point substance abuse scale was constructed with values anchored by never used drugs (1)...

Individual differences in the variance of event-related potential (ERP) slow wave (SW) measures were examined. SW was recorded at prefrontal and parietal sites during memory and sensory trials of a delayed-response task in 391 adolescent twin pairs. Familial resemblance was identified and there was a strong suggestion of genetic influence. A common genetic factor influencing memory and sensory ...

The timing of puberty is complex, possibly involving many genetic factors that may interact with environmental influences. Familial resemblance for age at menarche was studied in a sample of 4,995 female twins, 1,296 sisters, 2,946 mothers and 635 female spouses of male twins. They had indicated their age at menarche as part of a larger longitudinal survey. We assessed assortative mating for ag...

Although men are substantially more interested than women in casual sex, there is ample variation in this trait (sociosexuality) within both sexes. One theory hypothesizes that within-sex sociosexual variation results from genetic variation maintained by frequency-dependent selection. If so, sociosexuality should be substantially heritable. A competing theory is that children acquire their mati...

Standard genetic analyses assume that reciprocal heterozygotes are, on average, phenotypically identical. If a locus is subject to genomic imprinting, however, this assumption does not hold. We incorporate imprinting into the standard quantitative-genetic model for two alleles at a single locus, deriving expressions for the additive and dominance components of genetic variance, as well as measu...