ON THE EVOLUTION OF GENOME SIZE OF BIRDS
ON THE EVOLUTION OF GENOME SIZE OF BIRDS
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DOI：
10.1093/oxfordjournals.jhered.a111105
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发表时间：
1991-09-01
影响因子：
3.1
通讯作者：
WACHTEL, SS
中科院分区：
文献类型：
--
作者：
TIERSCH, TR;WACHTEL, SS
我们测量了基因组大小（核DNA含量）的荧光流式细胞术在55种鸟类代表12个不同的目的。实验室使用Feulgen染色细胞核的吸收细胞光度法在大约100个物种中进行了类似的研究。虽然用作参考的物种的赋值存在明显差异，但在不同实验室获得的值通常是一致的。当数据相对于家鸡的2.5皮克（pg）DNA的二倍体（2C）值标准化时，（Gallus gallus arcticus），代表17个目的135个物种的平均DNA含量为2.82 +/- 0.33（SD）pg，范围为2.0-3.8 pg。因此，鸟类的基因组大小是任何脊椎动物纲中最保守的，所有考虑的数值都比以前的估计所显示的小，而且大小更均匀。这可以用一个以前未被探索的假设来解释：鸟类的基因组是从一个小的祖先基因组进化而来的，这个祖先基因组在原始鸟类出现之前就已经减少了。
We measured genome size (nuclear DNA content) by fluorescence flow cytometry in 55 species of birds representing 12 different orders. Similar studies were performed in approximately 1 00 species by laboratories using absorption cytophotometry of Feulgen-stained nuclei. Although there have been apparent discrepancies in the assigned values for the species used as a reference, the values obtained in the different laboratories are generally in agreement. When the data are standardized in relation to a diploid (2C) value of 2.5 picograms (pg) of DNA for the domestic chicken (Gallus gallus domesticus), the mean for DNA content in 135 species representing 17 orders is 2.82 +/- 0.33 (SD) pg with a range of 2.0-3.8 pg. Thus the genome size of birds is the most conservative of any vertebrate class and, all values considered, is smaller and more uniform in size than previous estimates would indicate. This could be explained by a previously unexplored hypothesis: that the genome of birds has evolved from a small ancestral genome that was reduced before emergence of the protoavian.