Spore-autonomous fluorescent protein expression identifies meiotic chromosome mis-segregation as the principal cause of hybrid sterility in yeast
Spore-autonomous fluorescent protein expression identifies meiotic chromosome mis-segregation as the principal cause of hybrid sterility in yeast
复制标题
孢子自主荧光蛋白表达确定减数分裂染色体错误分离是酵母杂交不育的主要原因
作者：
D. W. Rogers;Ellen McConnell;Jasmine Ono;D. Greig
群体之间的全基因组序列差异可以通过抗重组系统的作用导致杂种不育，该系统拒绝不相同序列之间的双链断裂的交叉修复。由于交换是必要的，以确保在减数分裂过程中同源染色体的适当分离，降低重组率在杂种可能会导致高水平的不分离，因此低配子活力。杂交不育在种间杂交的酵母菌是已知的与这种分离错误，但估计的重要性不分离后合子生殖隔离已受到阻碍的困难，准确地测量不分离频率。在这里，我们使用孢子自主荧光蛋白表达来量化种间和种内酵母杂交不分离。我们表明，分离是近随机种间杂种。观察到的不分离率可以解释大多数种间杂种中观察到的不育性，通过配子不能遗传每个染色体的至少一个拷贝。通过阻止RecQ解旋酶SGS1在减数分裂期间的表达来部分地削弱抗重组系统，将不分离频率减半。我们进一步表明，染色体丢失通过不分离可以解释几乎所有的不育性观察到的杂种形成的两个种群之间的一个单一的物种。在这些种内杂种中，每对同源染色体的减数分裂不分离率与染色体大小呈负相关。我们的研究结果表明，序列的分歧不仅与不育的杂交种之间形成的远亲物种，但也可能是一个直接的原因，生殖隔离的早期物种。
Genome-wide sequence divergence between populations can cause hybrid sterility through the action of the anti-recombination system, which rejects crossover repair of double strand breaks between nonidentical sequences. Because crossovers are necessary to ensure proper segregation of homologous chromosomes during meiosis, the reduced recombination rate in hybrids can result in high levels of nondisjunction and therefore low gamete viability. Hybrid sterility in interspecific crosses of Saccharomyces yeasts is known to be associated with such segregation errors, but estimates of the importance of nondisjunction to postzygotic reproductive isolation have been hampered by difficulties in accurately measuring nondisjunction frequencies. Here, we use spore-autonomous fluorescent protein expression to quantify nondisjunction in both interspecific and intraspecific yeast hybrids. We show that segregation is near random in interspecific hybrids. The observed rates of nondisjunction can explain most of the sterility observed in interspecific hybrids through the failure of gametes to inherit at least one copy of each chromosome. Partially impairing the anti-recombination system by preventing expression of the RecQ helicase SGS1 during meiosis cuts nondisjunction frequencies in half. We further show that chromosome loss through nondisjunction can explain nearly all of the sterility observed in hybrids formed between two populations of a single species. The rate of meiotic nondisjunction of each homologous pair was negatively correlated with chromosome size in these intraspecific hybrids. Our results demonstrate that sequence divergence is not only associated with the sterility of hybrids formed between distantly related species but may also be a direct cause of reproductive isolation in incipient species.
登录
查看更多内容
影响因子：
3.2
作者：
Cogliati, Massimo;D'Amicis, Roberta;Colom, Maria F.
通讯作者：
Colom, Maria F.
影响因子：
3.2
作者：
J. Hou;Téo Fournier;J. Schacherer
通讯作者：
J. Hou;Téo Fournier;J. Schacherer
影响因子：
2.5
作者：
Hou,Jing;Schacherer,Joseph
通讯作者：
Schacherer,Joseph
影响因子：
16
作者：
Oh, Steve D.;Lao, Jessica P.;Taylor, Andrew F.;Smith, Gerald R.;Hunter, Neil
通讯作者：
Hunter, Neil
DOI：
10.1073/pnas.94.18.9757
发表时间：
1997-09-02
影响因子：
11.1
作者：
Datta, A;Hendrix, M;JinksRobertson, S
通讯作者：
JinksRobertson, S