Pichia sorbitophila, an Interspecies Yeast Hybrid, Reveals Early Steps of Genome Resolution After Polyploidization.
Pichia sorbitophila, an Interspecies Yeast Hybrid, Reveals Early Steps of Genome Resolution After Polyploidization.
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DOI：
10.1534/g3.111.000745
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发表时间：
2012-02
期刊：
影响因子：
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通讯作者：
Souciet JL
中科院分区：
文献类型：
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作者：
Louis VL;Despons L;Friedrich A;Martin T;Durrens P;Casarégola S;Neuvéglise C;Fairhead C;Marck C;Cruz JA;Straub ML;Kugler V;Sacerdot C;Uzunov Z;Thierry A;Weiss S;Bleykasten C;De Montigny J;Jacques N;Jung P;Lemaire M;Mallet S;Morel G;Richard GF;Sarkar A;Savel G;Schacherer J;Seret ML;Talla E;Samson G;Jubin C;Poulain J;Vacherie B;Barbe V;Pelletier E;Sherman DJ;Westhof E;Weissenbach J;Baret PV;Wincker P;Gaillardin C;Dujon B;Souciet JL
多倍化是真核生物基因组进化中的一个重要过程，但其分子机制仍有待阐明。同源多倍体化或全基因组重复事件经常在所产生的谱系中通过大多数重复对中的单个基因的丢失而解决，从而导致瞬时基因剂量失衡并通过减数分裂不育加速物种形成。异源多倍化或种间杂种的形成引起了遗传不亲和性的问题（Bateson-Dobzhansky-Muller效应），并且可以通过在所产生的谱系中积累突变变化来解决。在这篇文章中，我们表明，一个耐酒精的酵母物种，毕赤酵母，最近在工业中分离的浓缩山梨醇溶液，说明了这最后一种情况。它的基因组是同源和同源染色体的镶嵌体，或其部分，对应于进化过程中最近形成的杂种。使用GC含量的现有变化来表征该基因组的相应亲本贡献。鉴定了在杂种形成后的短时期内发生的基因组变化（例如，杂合性丢失、rDNA的单侧丢失、相互交换）并与两个亲本基因组在与它们的共同祖先分离后所经历的那些（即，NUMT（线粒体起源的NUclear序列）插入、基因获取、基因定位移动、相互易位）。我们发现，这种新的酵母物种的生理特性是由特定的，但不平等的贡献，它的两个父母，其中一个可以被确定为非常密切相关的一个现存的Pichia farinosa菌株。
Polyploidization is an important process in the evolution of eukaryotic genomes, but ensuing molecular mechanisms remain to be clarified. Autopolyploidization or whole-genome duplication events frequently are resolved in resulting lineages by the loss of single genes from most duplicated pairs, causing transient gene dosage imbalance and accelerating speciation through meiotic infertility. Allopolyploidization or formation of interspecies hybrids raises the problem of genetic incompatibility (Bateson-Dobzhansky-Muller effect) and may be resolved by the accumulation of mutational changes in resulting lineages. In this article, we show that an osmotolerant yeast species, Pichia sorbitophila, recently isolated in a concentrated sorbitol solution in industry, illustrates this last situation. Its genome is a mosaic of homologous and homeologous chromosomes, or parts thereof, that corresponds to a recently formed hybrid in the process of evolution. The respective parental contributions to this genome were characterized using existing variations in GC content. The genomic changes that occurred during the short period since hybrid formation were identified (e.g., loss of heterozygosity, unilateral loss of rDNA, reciprocal exchange) and distinguished from those undergone by the two parental genomes after separation from their common ancestor (i.e., NUMT (NUclear sequences of MiTochondrial origin) insertions, gene acquisitions, gene location movements, reciprocal translocation). We found that the physiological characteristics of this new yeast species are determined by specific but unequal contributions of its two parents, one of which could be identified as very closely related to an extant Pichia farinosa strain.