Open AccessA developing paradigm for the development of bird beaks
Author(s) -
GRANT PETER R.,
GRANT B. ROSEMARY,
ABZHANOV ARKHAT
Publication year - 2006
Publication title -
biological journal of the linnean society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.906
H-Index - 112
eISSN - 1095-8312
pISSN - 0024-4066
DOI - 10.1111/j.1095-8312.2006.00595.x
Subject(s) - biology , adaptive radiation , heterochrony , cichlid , evolutionary biology , anolis , natural selection , vertebrate , trait , sexual selection , interspecific competition , adaptation (eye) , ecology , gene , selection (genetic algorithm) , genetics , fish <actinopterygii> , phylogenetics , lizard , artificial intelligence , fishery , neuroscience , ontogeny , computer science , programming language
Some adaptive radiations are notable for extreme interspecific diversification in one or a few adult traits. How and why have trait differences evolved? Natural and sexual selection often provide answers to the question of why. An answer to the question of how is to be found in the genetic control of the phenotypic traits, especially in the early stages of development, when interspecific differences first become expressed. Recent studies of the molecular genetic control of beak development in Darwin's finches have shown that a signalling molecule (BMP4) plays a key role in the development of large and deep beaks. Expression of this molecule occurs earlier (heterochrony) and at higher levels in species with deep beaks compared with species with more pointed beaks. The implication of this finding is that variation in the regulation of one or a few genes that are expressed early could be the source of evolutionarily significant variation that is subject to natural selection in speciation and adaptive radiation. This view is reinforced by parallel findings with the same signalling molecule in the development of jaw morphology in cichlid fish of the Great Lakes of Africa. Further research into regulatory mechanisms is to be expected, as well as extension to other examples of radiation such as honeycreepers in Hawaii and Anolis lizards in the Caribbean. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 88 , 17–22.