TAILIEUCHUNG - Báo cáo sinh học: " Sperm dumping as a defense against meiotic drive"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Sperm dumping as a defense against meiotic drive. | Journal of Biology BioMed Central Minireview Sperm dumping as a defense against meiotic drive Tom Price Zenobia Lewis1 and Nina Wedell Address Ecology and Conservation School of Biosciences Cornwall Campus Penryn Cornwall TR10 9EZ UK. fGraduate School of Environmental Science Okayama University Okayama 700-8530 Japan. Correspondence Tom Price. Email Published 20 January 2009 Journal of Biology 2009 8 6 The electronic version of this article is the complete one and can be found online at http content 8 1 6 2009 BioMed Central Ltd Abstract Sperm from Drosophila simulans that carry a sex-ratio distorter is preferentially lost from females sperm-storage organs. This suggests that sperm dumping is a major factor affecting sperm competition in this species and may have evolved in response to sex-ratio distorters. Meiotic drivers are genes that subvert the normal rules of inheritance to ensure that they are present in more than their fair share of gametes in the next generation 1 . For example the driver sex-ratio SR in the fruit fly Drosophila simulans is an X chromosome that is present in all the sperm produced by male carriers thus causing SR males to produce only daughters Figure 1 . This is because sperm carrying the Y chromosome in these males fails to develop properly. Early genetic analyses suggested that these drivers should increase in frequency in the population as male carriers pass the driver on to all their offspring 1 2 . The SR was also predicted to outcompete normal X chromosomes because of the increased number of offspring in the population receiving the driving X. Eventually the driver should reach such a high frequency that the population would consist entirely of females - and would go extinct. In reality drivers do not seem to spread to fixation. In wild populations drivers are often found at a low but stable frequency and in laboratory populations SR and other drivers are usually outcompeted by non-driving .

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