Schwander: Genes as leaders and followers in evolution

[Darwinsbulldog]

Schwander, T. and O. Leimar (2011). "Genes as leaders and followers in evolution." Trends in Ecology & Evolution 26(3): 143-151.

A major question for the study of phenotypic evolution is whether intra- and interspecific diversity originates directly from genetic variation, or instead, as plastic responses to environmental influences initially, followed later by genetic change. In species with discrete alternative phenotypes, evolutionary sequences can be inferred from transitions between environmental and genetic phenotype control, and from losses of phenotypic alternatives. From the available evidence, sequences appear equally probable to start with genetic polymorphism as with polyphenism, with a possible dominance of one or the other for specific trait types. We argue in this review that to evaluate the prevalence of each route, an investigation of both genetic and environmental cues for phenotype determination in several related rather than in isolated species is required.

http://www.sciencedirect.com/science...69534710003022

Not open source but....for example:-

http://www.tru.ca/faculty/mreudink/4...mar%202011.pdf

A nice little review from TREE complete with a glossary for the jargon. Well worth the read. This question has become more important since the discovery of epigenetic change. {Epigenetics is the process where a trait in the parent is passed on to the offspring, [perhaps for several generations, or sometimes for longer periods] without a change in gene sequencing}. Sometimes an epigenetic change can spread though the whole population, and therefore become "fixed".

An example of "epi" is in fruit flies, where the mother's Hox transcription factor gives "polarity" to the egg. Thus the anterior-posterior axis [front to rear] orientation is defined. Another example is in humans, where male factors try to give the baby a large head, but female expression favours a smaller head, due to the limits of the birth canal. The result of this conflict is usually a compromise.

This post was sponsored by the following smilie: