Critical role of insertion preference for invasion trajectory of transposons
Critical role of insertion preference for invasion trajectory of transposons
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DOI：
10.1093/evolut/qpad128
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发表时间：
2023-08-05
期刊：
影响因子：
3.3
通讯作者：
Brandvain，Yaniv
中科院分区：
文献类型：
--
作者：
Munasinghe，Manisha;Springer，Nathan;Brandvain，Yaniv
目前还不清楚移动的DNA序列（转座因子，以下简称TE）如何侵入真核生物基因组并达到稳定的拷贝数，因为转座可以降低宿主适应性。这种挑战在TE家族入侵的早期尤其严峻，此时宿主可能缺乏抑制这些TE传播的专门机制。一种可能性（除了TE的宿主调节的进化之外）是TE家族可能进化为优先插入不太可能影响宿主适合度的染色体区域。这可以允许平均TE拷贝数增长，同时使宿主种群灭绝的风险最小化。为了验证这一点，我们构建了模拟来探索TE家族的转座概率和插入偏好如何影响平均TE拷贝数和宿主群体大小的演变，从而导致灭绝。我们发现，TE家庭的插入偏好的效果取决于主机的能力，以调节这个TE家庭。如果没有宿主抑制，中性插入偏好会增加种群灭绝的频率，并缩短种群灭绝的时间。在宿主阻遏的情况下，中性插入的偏好最大限度地减少了累积的有害负荷，增加了种群适应性，并最终避免触发灭绝漩涡。
It is unclear how mobile DNA sequences (transposable elements, hereafter TEs) invade eukaryotic genomes and reach stable copy numbers, as transposition can decrease host fitness. This challenge is particularly stark early in the invasion of a TE family at which point hosts may lack the specialized machinery to repress the spread of these TEs. One possibility (in addition to the evolution of host regulation of TEs) is that TE families may evolve to preferentially insert into chromosomal regions that are less likely to impact host fitness. This may allow the mean TE copy number to grow while minimizing the risk for host population extinction. To test this, we constructed simulations to explore how the transposition probability and insertion preference of a TE family influence the evolution of mean TE copy number and host population size, allowing for extinction. We find that the effect of a TE family’s insertion preference depends on a host’s ability to regulate this TE family. Without host repression, a neutral insertion preference increases the frequency of and decreases the time to population extinction. With host repression, a preference for neutral insertions minimizes the cumulative deleterious load, increases population fitness, and, ultimately, avoids triggering an extinction vortex.