The ZW sex microchromosomes of an Australian dragon lizard share no homology with those of other reptiles or birds
The ZW sex microchromosomes of an Australian dragon lizard share no homology with those of other reptiles or birds
复制标题
DOI：
10.1007/s10577-009-9102-6
复制
发表时间：
2009-12-01
影响因子：
2.6
通讯作者：
Sarre, Stephen D.
中科院分区：
文献类型：
--
作者：
Ezaz, Tariq;Moritz, Benjamin;Sarre, Stephen D.
爬行动物显示出多种多样的性染色体系统，但值得注意的是，鸡的Z性染色体与壁虎（Gekko hokouensis）的ZW性染色体同源，这表明它们有着古老但共同的起源。这与蛇和一种软壳龟（Pelodiscus sinensis）的ZW性染色体相反，它们与鸡或彼此不同源，似乎是独立衍生的。在本文中，我们确定同源性，如果有的话，Pogona vitticeps的性染色体与蛇和鸡的5条蛇Z染色体基因（WAC，KLF6，TAX1BP 1，RAB 5A，和CTNNB1）和5个鸡Z染色体基因（ATP 5A1，GHR，DMRT 1，CHD 1，和APTX）的龙同源染色体的龙染色体的映射。蛇和鸡的性染色体基因的龙同源物分别定位于龙的第6和第2染色体，而鸟类性别决定基因DMRT 1不位于P.vitticeps的性染色体上。事实上，我们的数据表明，龙同源物的鸡Z染色体可能是完全包含在2号染色体中的P.vitticeps，这表明P.vitticeps的性别决定因子不是鸡的性别决定基因。鸡Z染色体与G. Hokouensis ZW染色体对被解释为保留了古老的ZW性染色体，在这种情况下，蛇和龙的非同源性性染色体将是独立的。我们的数据增加了另一个案例，独立派生的性染色体在有鳞爬行动物，这使得保留古老的性染色体同源性在有鳞动物不太可信。另外，鸟类Z染色体和G染色体之间的保守性也得到了证实。HokouensisZW染色体配对是巧合的，可能是趋同进化的一个例子，它作为Z染色体的地位在鸟类和G.河口。
Reptiles show a diverse array of sex chromosomal systems but, remarkably, the Z sex chromosomes of chicken are homologous to the ZW sex chromosomes of a species of gecko, Gekko hokouensis, suggesting an ancient but common origin. This is in contrast to the ZW sex chromosomes of snakes and a species of soft-shelled turtle, Pelodiscus sinensis, which are nonhomologous to those of chicken or each other and appear to have been independently derived. In this paper, we determine what homology, if any, the sex chromosomes of the Australian dragon lizard Pogona vitticeps shares with those of snake and chicken by mapping the dragon homologs of five snake Z chromosome genes (WAC, KLF6, TAX1BP1, RAB5A, and CTNNB1) and five chicken Z chromosome genes (ATP5A1, GHR, DMRT1, CHD1, and APTX) to chromosomes in the dragon. The dragon homologs of snake and chicken sex chromosome genes map to chromosomes 6 and chromosome 2, respectively, in the dragon and that DMRT1, the bird sex-determining gene, is not located on the sex chromosomes of P. vitticeps. Indeed, our data show that the dragon homolog to the chicken Z chromosome is likely to be wholly contained within chromosome 2 in P. vitticeps, which suggests that the sex-determining factor in P. vitticeps is not the sex-determining gene of chicken. Homology between chicken Z chromosome and G. hokouensis ZW chromosome pairs has been interpreted as retention of ancient ZW sex chromosomes in which case the nonhomologous sex chromosomes of snake and dragons would be independently derived. Our data add another case of independently derived sex chromosomes in a squamate reptile, which makes retention of ancient sex chromosome homology in the squamates less plausible. Alternatively, the conservation between the bird Z chromosome and the G. hokouensis ZW chromosomes pairs is coincidental, may be an example of convergent evolution, its status as the Z chromosome having been independently derived in birds and G. hokouensis.