大規模測序揭示人精子基因組在減數分裂過程的變異情況
作者:
小柯機器人發布時間:2020/6/5 8:53:08
美國哈佛醫學院Steven A. McCarroll、Avery Davis Bell及其課題組,通過對31,228個人精子基因組進行研究揭示了精子在減數分裂過程中的變異情況。 相關論文在線發表在2020年6月3日的《自然》上。
為了研究減數分裂的各個過程以及它們如何在染色體、配子和人類之間發生變化,研究人員開發了Sperm-seq技術,這是一種能同時分析成千上萬個單精子基因組的方法。
研究人員對來自20個精子供體的31,228個人精子基因組進行了分析,確定了813,122個交叉點和787個非整倍染色體。供體精子的非整倍體率為每配子0.01至0.05。交叉部分保護染色體免受減數分裂I期細胞分裂時的非分離作用。
在減數分裂I期,某些染色體和供體進行頻繁的非分離,而另一些染色體在減數分裂II期分離失敗的次數更多。精子基因組分析還揭示出許多基因組異常,其無法通過簡單的非分離來解釋。從交叉速率到交叉位置和分離、一種交叉幹擾的量度、不同的重組表型在個體和細胞之間變化很大。該研究結果可與早期的研究結果整合為一個統一的模型,即核心機制、減數分裂染色體的可變物理收縮會在不同的減數分裂表型中產生個體以及細胞間的差異。
據悉,雖然減數分裂是繁殖所必需的,但同時該過程也是易變且容易出錯的。配子之間、性別之間以及同性人類之間的染色體交換速率各不相同,並且染色體錯位導致異常的染色體數(非整倍性)。
附:英文原文
Title: Insights into variation in meiosis from 31,228 human sperm genomes
Author: Avery Davis Bell, Curtis J. Mello, James Nemesh, Sara A. Brumbaugh, Alec Wysoker, Steven A. McCarroll
Issue&Volume: 2020-06-03
Abstract: Meiosis, although essential for reproduction, is also variable and error-prone: rates of chromosome crossover vary among gametes, between the sexes, and among humans of the same sex, and chromosome missegregation leads to abnormal chromosome numbers (aneuploidy)1,2,3,4,5,6,7,8. To study diverse meiotic outcomes and how they covary across chromosomes, gametes and humans, we developed Sperm-seq, a way of simultaneously analysing the genomes of thousands of individual sperm. Here we analyse the genomes of 31,228 human gametes from 20 sperm donors, identifying 813,122 crossovers and 787 aneuploid chromosomes. Sperm donors had aneuploidy rates ranging from 0.01 to 0.05 aneuploidies per gamete; crossovers partially protected chromosomes from nondisjunction at the meiosis I cell division. Some chromosomes and donors underwent more-frequent nondisjunction during meiosis I, and others showed more meiosis II segregation failures. Sperm genomes also manifested many genomic anomalies that could not be explained by simple nondisjunction. Diverse recombination phenotypes—from crossover rates to crossover location and separation, a measure of crossover interference—covaried strongly across individuals and cells. Our results can be incorporated with earlier observations into a unified model in which a core mechanism, the variable physical compaction of meiotic chromosomes, generates interindividual and cell-to-cell variation in diverse meiotic phenotypes.
DOI: 10.1038/s41586-020-2347-0
Source: https://www.nature.com/articles/s41586-020-2347-0