Changing sex for selfish gain: B chromosomes of Lake Malawi cichlid fish
Changing sex for selfish gain: B chromosomes of Lake Malawi cichlid fish
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DOI：
10.1038/s41598-019-55774-8
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发表时间：
2019-12-27
影响因子：
4.6
通讯作者：
Kocher, Thomas D.
中科院分区：
文献类型：
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作者：
Clark, Frances E.;Kocher, Thomas D.
B染色体是额外的、非必需的染色体，存在于正常的A染色体补体之外。马拉维湖的许多种类的慈鲷携带单倍体，雌性限制性B染色体。在这里，我们发现这条B染色体表现出驱动，平均传输率为70%。b型传播雌虫的后代表现出强烈的雌性偏向性比例。这些后代的基因分型显示，B染色体携带一个女性性别决定因子，在连锁组7上对XY系统具有上位性优势。我们认为这种性别决定因子的进化是为了增强B染色体的减数分裂驱动。这是第一个证明女性减数分裂驱动可以导致新的性染色体入侵的证据，仅仅是为了使驱动者受益，而不是为了补偿扭曲的性别比例。
B chromosomes are extra, non-essential chromosomes present in addition to the normal complement of A chromosomes. Many species of cichlid fish in Lake Malawi carry a haploid, female-restricted B chromosome. Here we show that this B chromosome exhibits drive, with an average transmission rate of 70%. The offspring of B-transmitting females exhibit a strongly female-biased sex ratio. Genotyping of these offspring reveals the B chromosome carries a female sex determiner that is epistatically dominant to an XY system on linkage group 7. We suggest that this sex determiner evolved to enhance the meiotic drive of the B chromosome. This is some of the first evidence that female meiotic drive can lead to the invasion of new sex chromosomes solely to benefit the driver, and not to compensate for skewed sex ratios.