Heritability fitness

Table 1 shows the twin correlations and model fitting heritability from Minnesota Study of Twins Reared Apart (MISTRA) for ten factors derived from a factor analysis of two widely used inventories, the Strong Vocational Interest Blank (Hansen Campbell, 1985) and the Jackson Vocational Interest Survey (Jackson, 1977). 

Scale Intraclass correlation MZA DZA (N=52) (N=27) Model-fitting heritability... 

Table 9. Intraclass correlations for MZT, DZT, MZA and DZA twins, number of pairs of twins and model-fitting heritability estimates for various religiousness measures...

Table 1. Intraclass correlations for MZA and DZA twins for ten factor scales derived from two interest inventories and heritabilities estimated by model-fitting...

For example, female first-degree relatives of women who have had breast cancer have a risk of breast cancer 2-3 times as great as normal, but the data do not fit any simple hypothesis. For most cancers, heritability is rather low. Therefore, the mutation component is likely to be low. There may be a mutation component acting through both germinal and somatic effects. If the two-mutation hypothesis for childhood tumors is correct, an environmental chemical could increase not only the frequency with which the first mutation would be inherited but also the frequency with which the second, somatic mutation would occur. Most calculations concerning retinoblastoma assume that the second mutation is almost certain to happen somewhere in the retina, provided that the first, inherited mutant gene is present. 

The biologic processes described above and cytosine methylation, fit the epigenetic definition well because they are heritable. However, whether the entire repertoire of histone modifications is heritable remains to be established. In fact, it is likely that only a subset will have epigenetic inheritance. 

Wiley, Chichester (Novartis Found Symp 233) p 260-275 Mousseau TA, Roff DA 1987 Natural selection and the heritability of fitness components. Heredity (Edinburgh) 59 181-197... 

Nesse That our minds are not designed to maximize fitness in the presence of birth control There is one implication I think is quite profound, which is that to the extent that there s heritability of a wish for having children (there s some evidence that there is heritability on that trait), this should be very strongly selected for. 

Miller Ify is principally a reflection of mutation load, and it s not a component of fitness but rather it is a subfactor of fitness, this might explain its heritability, the... 

Wiley, Chichester (Novartis Found Symp 223) p 260-275 Rice WR1988 Heritable variation in fitness as a prerequisite for adaptive female choice the effect of mutation-selection balance. Evolution 42 817-820 Rose M, Charlesworth B 1980 A test of evolutionary theories of senescence. Nature 287 141—142 Rushton JP 1995 Race, evolution, and behavior a life history perspective. Transaction, New Brunswick, NJ... 

Recent results based on a sample of Swedish twins reared together also provide general support for a reduction in common environment effects with age (McClearn et al 1997). Twins aged 80 years or more were studied and only those without cognitive or memory impairment were included. The estimated heritability was 0.62 and the shared environmental effect could be dropped without deterioration in fit of the model. 

The whole point of fitness indicators is to advertise differences in heritable fitness between individuals. This gives them some unusual features as biological adaptations, compared to ordinary survival adaptations (Miller 2000, Miller Todd 1998). Survival adaptations usually evolve to be genetically and developmentally canalized to create the optimal phenotype, leading to low apparent heritabihty and minimal differences between conspecifics. By contrast, fitness indicators evolve to be costly, complex displays that are so difficult to grow, maintain and produce that only the highest-fitness individuals can afford to produce them in the optimal, most sexually attractive form. Whereas survival adaptations tend to minimize between-individual differences, fitness indicators tend to amplify them dramatically (Hasson 1990, Pomiankowski Moller 1995, Rowe Houle 1996). 

Prediction 1. Factor analysis of reliable fitness measures obtained from a large representative sample of individuals from any wild species will reveal a general fitness factor, an JF factor, analogous to the g factor in psychometrics. This f factor will account for a substantial proportion of between-individual variance in the fitness measures, and will prove moderately heritable under normal ranges of environmental conditions. 

Prediction 3. Mate choice mechanisms should favour courtship behaviours with high -loadings, as cues of heritable fitness (insofar as g has a high /-loading). Generally, a mental trait s sexual attractiveness should correlate positively with its... 

Prediction 4. Most of our uniquely human mental abilities should show particularly high -loadings and /loadings, compared to more ancient mental capacities common to other great apes, primates or mammals. Like other sexually selected fitness indicators, they should also show higher coefficients of genetic variation and phenotypic variation, and at least moderate heritabilities. 

If the factor is subordinate to thef factor, then the surprisingly high heritability of human intelligence may reflect the heritability of fitness itself across many species. 

Charlesworth B 1987 The heritability of fitness. In Bradbury JW, Andersson MB (eds) Sexual selection testing the alternatives. Wiley, Chichester, p 21-40... 

Miller If one is aware of certain aspects of evolutionary theory, such as mutation—selection balance and strategic polymorphisms, they provide interesting competing accounts of why is so heritable and variable. Many of the measures of fitness and variance in animal species that have been developed provide interesting analogues of psychometric tests, and they might be mutually illuminating. They have been in this symposium. 

Many heritable mutations are correlated with a reduced fitness, i.e. a reduced survival probability of the offspring of the mutant. The reduction in average fitness with the arrival of new mutations is called mutation load (Crow and Kimura, 1970). However, the more deleterious a mutation is, the sooner it will... 

Charles Darwin laid out the basic rules by which populations evolve, emphasizing that three major elements are required variation among individuals, a link between variation and reproductive fitness, and heritability of the variation across generations (see 1 for review). Darwin traveled the world to accumulate evidence for the evolution of populations by natural selection, and found it in fossils and populations separated for millions of years (2). But 150 years later, we can often see evolution occurring on our very doorsteps and can document rates of evolutionary change that would have astounded Darwin. 

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