The genetic and molecular architecture of phenotypic diversity in sticklebacks

Abstract

One contribution of 17 to a theme issue 'Evodevo in the genomics era, and the origins of morphological diversity'. A major goal of evolutionary biology is to identify the genotypes and phenotypes that underlie adaptation to divergent environments. Stickleback fish, including the threespine stickleback (Gasterosteus aculeatus) and the ninespine stickleback (Pungitius pungitius), have been at the forefront of research to uncover the genetic and molecular architecture that underlies phenotypic diversity and adaptation. A wealth of quantitative trait locus (QTL) mapping studies in sticklebacks have provided insight into longstanding questions about the distribution of effect sizes during adaptation as well as the role of genetic linkage in facilitating adaptation. These QTL mapping studies have also provided a basis for the identification of the genes that underlie phenotypic diversity. These data have revealed that mutations in regulatory elements play an important role in the evolution of phenotypic diversity in sticklebacks. Genetic and molecular studies in sticklebacks have also led to new insights on the genetic basis of repeated evolution and suggest that the same loci are involved about half of the time when the same phenotypes evolve independently. When the same locus is involved, selection on standing variation and repeated mutation of the same genes have both contributed to the evolution of similar phenotypes in independent populations. This article is part of the themed issue 'Evo-devo in the genomics era, and the origins of morphological diversity'.

Perspectives on the history of evo-devo and the contemporary research landscape in the genomics era

“…B 372: 20150473 for the phenotypic differences (for a detailed example, see [62]). However, even in stickleback, as Piechel and Marques point out [58], it remains to be seen whether all the different morphological features seen in different populations are based on such changes. Sequence differences in a cis-regulatory region have also been suggested to underlie morphological diversification in vertebrate limbs (discussed in the article by Cooper and coworkers [54]).…”

“…The next section focuses on diversification and modifications of morphology as exemplified by tetrapod limbs by Saxena et al [54], flowers by Pam Soltis and co-workers [55], cranial shape in birds by Abzhanov and co-workers [45] and wing coloration patterns in butterflies by Jiggins et al [56]. The last section considers the relatively recent evolution of genetically determined morphological variation within a single species owing to either natural selection, using as examples, cavefish (article by Krishnan & Rohner [57]) and stickleback (article by Piechel & Marques [58]) or artificial selection, using dogs as an example (article by Elaine Ostrander and co-workers [59]) and ends with the article on developmental plasticity by Xu & Zhang [49].…”

“…An important advance has been the establishment of model systems that can be thought of as exemplifying 'evolution in action'. The two examples discussed in this issue are the natural populations of cavefish [57] and stickleback [58] with diverse morphologies that live in different environments.…”

“…The stunning coloured patterns of the wings of the different species of Heliconius butterflies provide outstanding examples in which a gene is expressed in a new context and takes on a completely new function [56]. Striking examples of changes in cis-regulatory regions underlying morphological diversity are also found in natural populations of stickleback [58]. What is particularly exciting about the stickleback system is that it has been possible to prove experimentally that the genetic changes affect the function of cis-regulatory regions of key developmental genes and that these changes are responsible rstb.royalsocietypublishing.org Phil.…”

“…A long-standing question is whether evolution is based on changes in a few genes that have a large effect or on a combination of changes in many genes that each has a small effect. Interestingly, Harrison points out that single-gene mutations can produce a major changes in plant morphology relevant to evolutionary innovations [53], whereas the analysis of morphological characteristics of stickleback by Piechel & Marques [58] demonstrates that, similarly, changes in the activity of a few large effect genes are responsible for diversification. In addition, Jiggins et al [56] point out that only four major genetic loci control most of the variation in wing coloration patterns in Heliconius butterflies.…”