Physical Mapping and Refinement of the Painted Turtle Genome (Chrysemys picta) Inform Amniote Genome Evolution and Challenge Turtle-Bird Chromosomal Conservation.
Physical Mapping and Refinement of the Painted Turtle Genome (Chrysemys picta) Inform Amniote Genome Evolution and Challenge Turtle-Bird Chromosomal Conservation.
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DOI：
10.1093/gbe/evv119
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发表时间：
2015-06-24
影响因子：
3.3
通讯作者：
Valenzuela N
中科院分区：
文献类型：
--
作者：
Badenhorst D;Hillier LW;Literman R;Montiel EE;Radhakrishnan S;Shen Y;Minx P;Janes DE;Warren WC;Edwards SV;Valenzuela N
比较基因组学继续阐明了人类基因组的进化，但对于许多谱系，我们的理解仍然不完整。在这里，我们完善的大会（CPI 3.0.3 NCBI AHGY0000000.2），并制定了一个细胞遗传学图谱的彩绘龟（Aimemys picta-CPI）的基因组，第一次在海龟和脊椎动物的温度依赖性性别决定。龟的基因组与鸡，选定的非鸟类爬行动物和人类的基因组的比较揭示了共同的和新的基因组特征，如许多染色体重排。鸟类和海龟之间最大的保守同线块存在于四个宏染色体中，而重排在这些和其他染色体中是明显的，反驳海龟和鸟类保留了超过3亿年的完全保守的宏染色体。C带显示只有少数染色体的着丝粒区域有大的异染色质块。核仁组织区（NOR）映射到一个单一的CPI微染色体，而在一些海龟和蜥蜴的NOR映射到非同源性染色体，从而揭示了独立的易位的NOR在各种爬行动物的血统。没有证据表明最近的染色体融合，因为间质端粒DNA不存在。一些重复元件（CR 1样、Gypsy）富集在五条染色体的着丝粒中，而其他重复元件则广泛存在于CPI基因组中。将细菌人工染色体（BAC）克隆与25条CPI染色体中的18条杂交，并锚定到G带表意图上。几个CPI性别决定基因映射到五条染色体，和同源性之间检测到其他CPI常染色体和全球非同源性染色体的鸡，其他龟，和有鳞动物，强调脊椎动物性别决定机制的独立进化。
Comparative genomics continues illuminating amniote genome evolution, but for many lineages our understanding remains incomplete. Here, we refine the assembly (CPI 3.0.3 NCBI AHGY00000000.2) and develop a cytogenetic map of the painted turtle (Chrysemys picta—CPI) genome, the first in turtles and in vertebrates with temperature-dependent sex determination. A comparison of turtle genomes with those of chicken, selected nonavian reptiles, and human revealed shared and novel genomic features, such as numerous chromosomal rearrangements. The largest conserved syntenic blocks between birds and turtles exist in four macrochromosomes, whereas rearrangements were evident in these and other chromosomes, disproving that turtles and birds retain fully conserved macrochromosomes for greater than 300 Myr. C-banding revealed large heterochromatic blocks in the centromeric region of only few chromosomes. The nucleolar-organizing region (NOR) mapped to a single CPI microchromosome, whereas in some turtles and lizards the NOR maps to nonhomologous sex-chromosomes, thus revealing independent translocations of the NOR in various reptilian lineages. There was no evidence for recent chromosomal fusions as interstitial telomeric-DNA was absent. Some repeat elements (CR1-like, Gypsy) were enriched in the centromeres of five chromosomes, whereas others were widespread in the CPI genome. Bacterial artificial chromosome (BAC) clones were hybridized to 18 of the 25 CPI chromosomes and anchored to a G-banded ideogram. Several CPI sex-determining genes mapped to five chromosomes, and homology was detected between yet other CPI autosomes and the globally nonhomologous sex chromosomes of chicken, other turtles, and squamates, underscoring the independent evolution of vertebrate sex-determining mechanisms.