Karyotype Analysis of Four Blind Snake Species (Reptilia: Squamata: Scolecophidia) and Karyotypic Changes in Serpentes
Karyotype Analysis of Four Blind Snake Species (Reptilia: Squamata: Scolecophidia) and Karyotypic Changes in Serpentes
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DOI：
10.1159/000496554
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发表时间：
2019-01-01
影响因子：
1.7
通讯作者：
Matsuda, Yoichi
中科院分区：
文献类型：
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作者：
Matsubara, Kazumi;Kumazawa, Yoshinori;Matsuda, Yoichi
蛇亚目分为两个下目，Scolecophidia和Alethinophidia，这在蛇的多样化的早期阶段分歧。本研究对4种锦蛇（Letheobia simonii，Xerotyphlops verticularis，Indotyphlops braminus，Myriopholis macrorhyncha）的核型进行了研究，并利用18 S-28 S rDNA以及四条锦蛇（Elaphe quadrivirgata，Alethinophidia）的微染色体和Z染色体连锁基因进行了FISH分析，以探讨锦蛇的核型演化。二倍体染色体数目。蠕虫L. simonii的染色体数目分别为30条（16条大染色体和14条小染色体）和32条（16条大染色体和16条小染色体）。本文报道了一种雌性M.大喙龙由15条大染色体和19条小染色体组成，其中包括一条异染色质小染色体，表明存在一对异形染色体。E. quadrivirgata的Z连锁基因定位于M. macrorhyncha，而不是异形对。因此，M。巨吻龙可能具有与E. quadrivirgata。其中一个E. quadrivirgata微染色体基因定位于X.蠕虫，这表明在该物种中发生了小染色体和大染色体之间的融合。rDNA定位在不同的大染色体对在这里检查的2个二倍体蛇，而在一个微染色体对的基因位置是保守的5个alethinophidian物种检查。这些结果可能意味着在真蛇科谱系中发生了染色体融合。在重症Braminus是一种独特的孤雌生殖蛇，具有三倍体核型（21条大染色体和21条小染色体），在第1和第7染色体上鉴定出形态异形。这种2条染色体上的异态在该物种广泛分布范围内的遥远地点的个体中也被观察到，这表明这种异态在其物种形成的早期阶段就被固定在基因组中。(C)2019 S. Karger AG，巴塞尔
The suborder Serpentes is divided into 2 infraorders, Scolecophidia and Alethinophidia, which diverged at an early stage of snake diversification. In this study, we examined karyotypes of 4 scolecophidian species (Letheobia simonii, Xerotyphlops vermicularis, Indotyphlops braminus, and Myriopholis macrorhyncha) and performed FISH with 18S-28S rDNA as well as microchromosomal and Z chromosome-linked genes of Elaphe quadrivirgata (Alethinophidia) to investigate the karyotype evolution in the scolecophidian lineage. Diploid chromosome numbers of X. vermicularis and L. simonii were 30 (16 macrochromosomes and 14 microchromosomes) and 32 (16 macrochromosomes and 16 microchromosomes), respectively. The karyotype of a female M. macrorhyncha consisted of 15 macrochromosomes and 19 microchromosomes, including a heterochromatic microchromosome, indicating the presence of a heteromorphic chromosome pair. E. quadrivirgata Z-linked genes mapped to chromosome 4 of M. macrorhyncha, not to the heteromorphic pair. Therefore, M. macrorhyncha may have differentiated ZW sex chromosomes which are not homologous to those of E. quadrivirgata. One of the E. quadrivirgata microchromosomal genes mapped to the terminal region of chromosome 4q in X. vermicularis, suggesting that fusions between microchromosomes and macrochromosomes occurred in this species. rDNA was localized in different macrochromosomal pairs in the 2 diploid scolecophidian snakes examined here, whereas the gene location in a microchromosomal pair was conserved in 5 alethinophidian species examined. These results might imply the occurrence of chromosome fusions in the scolecophidian lineages. In I. braminus, a unique parthenogenetic snake with a triploid karyotype (21 macrochromosomes and 21 microchromosomes), morphological heteromorphisms were identified in chromosomes 1 and 7. Such heteromorphisms in 2 chromosomes were also observed in individuals from distant locations in the broad distribution range of this species, suggesting that the heteromorphisms were fixed in the genome at an early stage of its speciation. (C) 2019 S. Karger AG, Basel