Crow J F
Department of Genetics, University of Wisconsin, Madison 53706.
Bioessays. 1991 Jun;13(6):305-12. doi: 10.1002/bies.950130609.
The precise 1:1 segregation of Mendelian heredity is ordinarily taken for granted, yet there are numerous examples of 'cheating' genes that perpetuate themselves in the population by biasing the Mendelian process in their favor. One example is the Segregation Distortion system of Drosophila melanogaster, in which the distorting gene causes its homologous chromosome to produce a nonfunctional sperm. This system depends on three closely linked components, whose molecular basis is beginning to be understood. The system is characterized by numerous modifiers changing the degree of distortion. Mathematical theory shows that unlinked modifiers that change the degree of distortion in the direction of Mendelism always increase in the population. This provides a mechanism for removing cheaters and preserving the honesty of the Mendelian gene-shuffle.
孟德尔遗传中精确的1:1分离通常被视为理所当然，但存在许多“作弊”基因的例子，这些基因通过使孟德尔过程向有利于它们的方向倾斜而在种群中延续自身。一个例子是黑腹果蝇的分离畸变系统，其中畸变基因导致其同源染色体产生无功能的精子。该系统依赖于三个紧密连锁的成分，其分子基础正开始被理解。该系统的特点是有许多改变畸变程度的修饰基因。数学理论表明，在孟德尔方向上改变畸变程度的非连锁修饰基因在种群中总是会增加。这提供了一种清除作弊者并保持孟德尔基因洗牌诚实性的机制。
