Genes, development, and evolvability in primate evolution

Abstract

Development is the process whereby a fertilized cell becomes a mature individual. In metazoans, this complex process involves the differentiation of somatic cells into committed cell and tissue types; the organization and migration of cells, tissues, and anatomical structures relative to one another; and growth. Development matters to evolution in two ways. First, development carries out heritable genetic instructions contained in zygotes to produce functioning yet phenotypically varied individuals. At the population level, this variation in form and function among individuals provides the "raw material" for evolution. Second, the mechanisms of development influence the magnitude, direction, and interdependence of heritable phenotypic variation among traits. Together with phenomena such as genetic drift, organismal development determines the raw material available to selection and thus influences the rate and direction of phenotypic evolution.

Constraint, natural selection, and the evolution of human body form

“…Limbs have a complex polygenic basis. They are found to be highly genetically correlated and exhibit strong pleiotropy when studied in a quantitative genetic framework (21,(41)(42)(43). When sample sizes are sufficient to render precise estimates of genetic correlations for morphological characters, the genetic and phenotypic correlations are nearly identical, implying a high degree of proportionality between genetic and phenotypic covariances (44,45).…”

“…1 (adapted with permission from ref. 21) shows this contrast graphically: if traits are uncorrelated, then they will respond to selection in the same direction as the force of selection irrespective of what direction in the morphospace selection is acting (Fig. 1A).…”

“…Alternatively, negative selection gradients between groups at different latitudes indicate a net negative relationship with fitness. We also decompose separate components of the net response to selection into the response of each trait arising from selection acting directly on a trait and the response driven by selection acting on correlated traits (21)(22)(23)(24)(25)(26)(27). To reemphasize, it is important to draw a distinction between the force of selection on a trait and the response to selection of that trait.…”

Genetic and developmental basis for parallel evolution and its significance for hominoid evolution

“…). For example, complex regulatory domains controlling Hox gene expression can produce modular changes in limb length and vertebral identity . In addition, limb growth has been shown to be affected by specific enhancers for another hind limb selector gene, Tbx4 .…”

Multivariate morphometrics, quantitative genetics, and neutral theory: Developing a “modern synthesis” for primate evolutionary morphology

“…First, there is a growing realization within evolutionary anthropology that the primate skeleton represents a complex, integrated system with varying levels of modularity based on genetic, developmental, and functional factors . Therefore, there is an urgent need to assimilate the multivariate form of different aspects of the skeleton (cranium and postcranium) in evolutionary studies so that we can build a better understanding of what the morphological units of evolution might be.…”