Gordon Jonathan L, Wolfe Kenneth H
Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland.
Yeast. 2008 Jun;25(6):449-56. doi: 10.1002/yea.1598.
Zygosaccharomyces rouxii strain ATCC 42981 has been reported to have two copies of several genes including HOG1 and SOD2, whereas the type strain of Z. rouxii (CBS 732) has only one. To investigate the structure of the ATCC 42981 genome we sequenced random fragments from this genome and compared the data to the type strain. We found that ATCC 42981 contains two versions of the ribosomal RNA array, one of which is identical in the ITS1-ITS2 and 26S D1/D2 regions to Z. rouxii CBS 732, while the other is almost identical to a species provisionally named Z. pseudorouxii. We found that most genomic regions from Z. rouxii CBS 732 map in a one-to-two fashion to pairs of regions in ATCC 42981, with one of the ATCC 42981 regions having 97-100% DNA sequence identity to CBS 732 and the other having about 80-90% identity. Complete sequencing of regions containing 30 pairs of genes from ATCC 42981 and their orthologues in CBS 732 showed no evidence of the gene deletions or pseudogene formation that might be expected if ATCC 42981 had undergone whole-genome duplication several million years ago and was in the early stages of gene loss. Instead, we conclude that ATCC 42981 is a Z. rouxii-Z. pseudorouxii interspecies hybrid that was formed so recently that its genome has not had time to decay.
据报道，鲁氏接合酵母菌株ATCC 42981有几个基因的两个拷贝，包括HOG1和SOD2，而鲁氏接合酵母模式菌株（CBS 732）只有一个拷贝。为了研究ATCC 42981基因组的结构，我们对该基因组的随机片段进行了测序，并将数据与模式菌株进行了比较。我们发现ATCC 42981包含核糖体RNA阵列的两个版本，其中一个在ITS1-ITS2和26S D1/D2区域与鲁氏接合酵母CBS 732相同，而另一个几乎与一个暂命名为拟鲁氏接合酵母的物种相同。我们发现，鲁氏接合酵母CBS 732的大多数基因组区域以一对一到二的方式映射到ATCC 42981中的区域对，其中ATCC 42981的一个区域与CBS 732的DNA序列同一性为97-100%，另一个区域的同一性约为80-90%。对包含ATCC 42981的30对基因及其在CBS 732中的直系同源基因的区域进行全序列测序，没有发现如果ATCC 42981在几百万年前经历了全基因组复制并且处于基因丢失的早期阶段可能预期的基因缺失或假基因形成的证据。相反，我们得出结论，ATCC 42981是一种鲁氏接合酵母-拟鲁氏接合酵母种间杂种，其形成时间非常近，以至于其基因组还没有时间发生衰变。
