Unusual origin of a nuclear pseudogene in the italian wall lizard:: Intergenomic and interspecific transfer of a large section of the mitochondrial genome in the genus Podarcis (Lacertidae)
Unusual origin of a nuclear pseudogene in the italian wall lizard:: Intergenomic and interspecific transfer of a large section of the mitochondrial genome in the genus Podarcis (Lacertidae)
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DOI：
10.1007/s00239-005-0259-0
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发表时间：
2007-03-01
影响因子：
3.9
通讯作者：
Mayer, Werner
中科院分区：
文献类型：
--
作者：
Podnar, Martina;Haring, Elisabeth;Mayer, Werner
两个不同的细胞色素b样序列被发现在基因组中的Podarcis sicula。其中一个代表线粒体序列的核拷贝（numt-sic），与从同一个体获得的真实线粒体（mt）序列相差14.3%。然而，这个numt与在一个种群的Podarcis muralis中发现的mt序列仅相差2.7%，Podarcis muralis是一个相关物种，其中没有检测到相应的numt。numt-sic序列延伸超过至少7637 bp，并且与从tRNA-Lys到tRNA-Pro基因的mt基因组部分同源。在numt-sic的9个蛋白质编码基因中的2个中检测到过早的mt终止密码子。三个密码子位置之间的置换和numt-sic序列的转换/颠换比的分布类似，除了少数例外，功能性mt基因的那些，表明相当近期转移到细胞核。对包括来自相同个体的P. sicula numt-cytb序列以及来自不同P. muralis种群的mt序列的数据集进行的系统发育分析表明，numt-sic起源于P. muralis。在地理调查中，P. sicula人口属于不同的mt谱系，覆盖了大部分的分布区，筛选numt-sic的存在和numt-nd 5序列中的15-bp重复多态性。我们的研究结果表明，numt-sic通过性传播的物种范围迅速蔓延，从而被转移到人口属于分离的山谱系分歧1-3百万年。
Two distinct cytochrome b-like sequences were discovered in the genome of Podarcis sicula. One of them represents a nuclear copy of a mitochondrial sequence (numt-sic) differing by 14.3% from the authentic mitochondrial (mt) sequence obtained from the same individual. This numt, however, differs by only 2.7% from the mt sequence found in one population of Podarcis muralis, a related species in which no corresponding numt was detected. The numt-sic sequence extends over at least 7637 bp and is homologous to a section of the mt genome spanning from the tRNA-Lys to the tRNA-Pro gene. Premature mt stop codons were detected in two of the nine protein coding genes of numt-sic. The distribution of substitutions among the three codon positions and the transition/transversion ratio of the numt-sic sequence resemble, with few exceptions, those of functional mt genes, indicating a rather recent transfer to the nucleus. Phylogenetic analyses performed on the data set including P. sicula numt-cytb sequences as well as mt-cytb sequences from the same individuals and mt sequences of various P. muralis populations suggest that numt-sic originated in P. muralis. In a geographic survey, P. sicula populations belonging to different mt lineages, covering most of the distribution area, were screened for the presence of numt-sic and for a 15-bp duplication polymorphism in the numt-nd5 sequence. Our results suggest that numt-sic has spread rapidly through the species range via sexual transmission, thereby being transferred to populations belonging to well-separated mt lineages that diverged 1-3 Mya.