據(jù)11月27日的《科學(xué)》雜志報(bào)道說(shuō),，研究人員對(duì)一個(gè)在進(jìn)化生物學(xué)中存在的長(zhǎng)期的謎團(tuán)提出了一種解決方法。該謎團(tuán)是關(guān)于新的物種是如何在沒(méi)有地理屏障區(qū)隔群落的情況下發(fā)展出來(lái)的,。 在一種經(jīng)典的場(chǎng)景中,，一個(gè)物種可分裂成2種或更多的被區(qū)隔的群落,，就像達(dá)爾文提到的雀科鳴禽在Galápagos Islands所發(fā)生的情況。 接著,，隨著時(shí)間的推移,，每一群落建立起了足夠的基因不兼容性，使得來(lái)自不同群落中的個(gè)體在進(jìn)行交配繁殖的時(shí)候,，其后代將沒(méi)有生育能力,。 但是，新物種的形成還可發(fā)生在那些不存在基因流動(dòng)物質(zhì)屏障的地區(qū)之中,。
G. Sander van Doorn及其同僚現(xiàn)在在一項(xiàng)理論研究中解釋說(shuō),，性別選擇可驅(qū)動(dòng)物種的形成，即雌性動(dòng)物更愿意與某些顯示了對(duì)局部環(huán)境具有良好適應(yīng)跡象的雄性動(dòng)物進(jìn)行交配,。 在這一模型中,，性別選擇發(fā)生在“歧化選擇”的背景之中，即雌性動(dòng)物更愿意選擇那些遺傳有極端性特征的配偶,，而非那些遺傳有中間性特征的配偶,。 例如，如果動(dòng)物必須要在一個(gè)黑與白的環(huán)境中偽裝自己的話,，那么,，那些長(zhǎng)著黑或白色毛皮的動(dòng)物可能會(huì)比那些長(zhǎng)著灰色毛皮的動(dòng)物更容易存活下來(lái)。 在這種情形下,，如果雌性動(dòng)物更愿意與那些具有顯示其對(duì)局部環(huán)境適應(yīng)良好的某種裝飾類型的雄性動(dòng)物進(jìn)行交配的話,，這將最終導(dǎo)致適應(yīng)情況較差并較少具備局部特征的動(dòng)物后代的減少。 因此,，自然選擇和性別選擇,，雖然人們常常假設(shè)它們之間存在著相互的沖突，其實(shí)它們能夠相互加強(qiáng),，從而導(dǎo)致新物種的形成,。（生物谷Bioon.com）
生物谷推薦原始出處：
Science November 26, 2009 DOI: 10.1126/science.1181661
On the Origin of Species by Natural and Sexual Selection
G. Sander van Doorn,1,2,*, Pim Edelaar,3,4,5,* Franz. J. Weissing3
Ecological speciation is considered an adaptive response to selection for local adaptation. However, besides suitable ecological conditions, the process requires assortative mating to protect the nascent species from homogenization by gene flow. By means of a simple model, we demonstrate that disruptive ecological selection favors the evolution of sexual preferences for ornaments that signal local adaptation. Such preferences induce assortative mating with respect to ecological characters and enhance the strength of disruptive selection. Natural and sexual selection thus work in concert to achieve local adaptation and reproductive isolation, even in the presence of substantial gene flow. The resulting speciation process ensues without the divergence of mating preferences, avoiding problems that have plagued previous models of speciation by sexual selection.
1 Santa Fe Institute, 1399 Hyde Park Rd., Santa Fe, NM 87501, USA.
2 Institute for Ecology and Evolution, University of Bern, Wohlenstrasse 50a, CH-3032 Hinterkappelen, Switzerland.
3 Centre for Ecological and Evolutionary Studies, University of Groningen, P.O. Box 14, 9750 AA Haren, The Netherlands.
4 Department of Animal Ecology, Uppsala University, Norbyv?gen 18 D, 752 36 Uppsala, Sweden.
5 Department of Conservation Biology, Estación Biológica de Do?ana CSIC, c/ Americo Vespucio s/n, 41092, Sevilla, Spain.
