Fitness-related patterns of genetic variation in rhesus macaques

Abstract

The patterning of quantitative genetic descriptions of genetic and residual variation for 15 skeletal and six life history traits was explored in a semi-free-ranging group of rhesus macaques (Macaca mulatta Zimmerman 1780). I tested theoretical predictions that explain the magnitude of genetic and residual variation as a result of 1. strength of a trait's association with evolutionary fitness, or 2. developmental and physiological relationships among traits. I found skeletal traits had higher heritabilities and lower coefficients of residual variation than more developmentally and physiologically dependent life history traits. Total lifetime fertility had a modest heritability (0.336) in this population, and traits with stronger correlations to fitness had larger amounts of residual variance. Censoring records of poorly-performing individuals on lifetime fertility and lifespan substantially reduced their heritabilities. These results support models for the fitness-related patterning of genetic variation based on developmental and physiological relationships among traits rather than the action of selection eroding variation.

Trade-off between age of first reproduction and survival in a female primate

“…The macaque results are consistent with this single human estimate. However, AFR in Finns was strongly influenced by maternal effects, while these are very small for female macaques (Blomquist 2009). An intriguing interpretation of this difference is that humans have evolved mechanisms to circumvent life-history trade-offs that are expressed in other female primates, possibly through the deliberate control and redistribution of resources within social groups, perhaps along kin lines, that results in the extension of parental effects to later ages (Cheverud & Moore 1994;Hawkes et al 1998;Kaplan & Robson 2002;Lee 2008).…”

“…Furthermore, female AFR is known to be heritable in the study population, making genetic covariance with other life-history traits plausible (Blomquist 2009). A life-history trade-off will be indicated by a positive relationship between AFR and adult survival, because when all other factors are held constant, decreasing AFR will increase lifetime fitness (Roff 2002).…”

Sexually selected skin colour is heritable and related to fecundity in a non-human primate

“…The population is now composed of 1000 individuals divided into naturally-formed groups, allowing male dispersal and gene flow. The population shows no significant effect of inbreeding [35,42], and the variance in lifetime reproductive success between individuals is sufficient to create opportunities for selection [43]. Date of birth, natal and current group, maternal ID, and matriline membership are provided by the CPRC.…”

A quantitative review of heterozygosity–fitness correlations in animal populations

“…Several comparative studies in the 1980s (Gustafsson 1986; confirmed the expectation that traits closely associated with individual fitness would have lower heritabilities than traits less tightly linked with fitness. More recent work has shown that the low heritability of fitness traits can be accounted for by high levels of residual variance (especially environmental variance) rather than low levels of additive genetic variance (Price & Schluter 1991;Kruuk et al 2000;Wilson et al 2006), and that, when scaled correctly, fitness traits can have higher additive genetic variance than nonfitness traits (Houle 1992;Kruuk et al 2000;Merilä & Sheldon 2000;Barton & Keightley 2002;McCleery et al 2004;Coltman et al 2005;Blomqvist 2009). Since fitness traits are expected to have a more complex polygenic architecture than morphological or physiological traits (Merilä & Sheldon 1999), this may also result in greater opportunity for correlations between fitness traits and neutral marker loci.…”