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Interlocus contest evolution (ICE) is a process of intergenomic conflict by which different loci within a single genome antagonistically coevolve. ICE supposes that the Red Queen process, which is characterized by a never-ending antagonistic evolutionary arms race, does not only apply to species but also to genes within the genome of a species.〔Rice & Holland, 1997. "The enemies within: intergenomic conflict, interlocus contest evolution (ICE), and the intraspecific Red Queen." Behavioral Ecology and Sociobiology 41(1): 1-10.〕 Because sexual recombination allows different gene loci to evolve semi-autonomously, genes have the potential to coevolve antagonistically. ICE occurs when "an allelic substitution at one locus selects for a new allele at the interacting locus, and vice versa." As a result, ICE can lead to a chain reaction of perpetual gene substitution at antagonistically interacting loci, and no stable equilibrium can be achieved. The rate of evolution thus increases at that locus.〔 ICE is thought to be the dominant mode of evolution for genes controlling social behavior.〔 The ICE process can explain many biological phenomena, including intersexual conflict, parent-offspring conflict, and interference competition. ==Intersexual conflict== (詳細はsexual reproduction. Genes expressed in only one sex are selectively neutral in the other sex; male- and female-linked genes can therefore be acted upon separated by selection and will evolve semi-autonomously.〔 Thus, one sex of a species may evolve to better itself rather than better the species as a whole, sometimes with negative results for the opposite sex: loci will antagonistically coevolve to enhance male reproductive success at females’ expense on the one hand, and to enhance female resistance to male coercion on the other.〔Trivers, R.L. 1972. "Parental investment and sexual selection." Sexual Selection and the Descent of Man, 1871–1971. Campbell, Aldine Publishing. 136–179.〕 This is an example of intralocus sexual conflict, and is unlikely to be resolved fully throughout the genome. However, in some cases this conflict may be resolved by the restriction of the gene’s expression to only the sex that it benefits, resulting in sexual dimorphism.〔Bonduriansky, R, SF Chenoweth. 2009. "Intralocus sexual conflict." Trends in Ecology & Evolution 24(5): 280-288.〕 The ICE theory can explain the differentiation of the human X- and Y-chromosomes. Semi-autonomous evolution may have promoted genes beneficial to females in the X-chromosome even when detrimental to males, and genes beneficial to males in the Y-chromosome, even when detrimental to females. As the distribution of the X-chromosome is three times as large as the Y-chromosome (the X-chromosome occurs in 3/4 of offspring genes, while the Y-chromosome occurs in only 1/4), the Y-chromosome has a reduced opportunity for rapid evolution. Thus the Y-chromosome has "shed" its genes to leave only the essential ones (such as the SRY gene), which gives rise to the differences in the X- and Y-chromosomes.〔Ridley, M. 2000. Genome: The Autobiography of a Species in 23 Chapters. Harper and Collins.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Interlocus contest evolution」の詳細全文を読む スポンサード リンク
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