High mutation rate and mutational bias at (TAA)n microsatellite loci in chickpea (Cicer arietinum L.)
High mutation rate and mutational bias at (TAA)n microsatellite loci in chickpea (Cicer arietinum L.)
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鹰嘴豆 (Cicer arietinum L.) (TAA)n 微卫星位点的高突变率和突变偏倚
DOI：
10.1007/s004380100568
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
M. Baum
中科院分区：
文献类型：
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作者：
S. Udupa;M. Baum
微卫星是非常短的串联重复DNA序列，由于其高度的等位基因变异性而被广泛用于农作物的进化遗传学和分子育种，这可能是由改变微卫星阵列长度的高突变率引起的。在人类和各种动物中，突变率差异很大，在10-3到10-6的范围内。在植物中，微卫星位点的突变率似乎高于动物中的突变率，但目前还没有实验估计。在这里，我们报告了鹰嘴豆近交群体中 15 个完美 (TAA)n 微卫星位点的高自发突变率 (μ) 和突变偏差。我们发现，与寿命较短的叙利亚本地品种（μ=3.9×10–3；在 15,600 个等位基因代中检测到）相比，长寿品种 Ghab 2（μ=1.0×10–2；在 16,050 个等位基因代中检测到）的所有位点平均突变率显着较高，两个品种中的大多数突变体 (96.9%) 的差异在于： ±1 重复单位。与动物相比，鹰嘴豆的突变率较高可能是由于存在长的 (TAA)n 微卫星重复阵列以及植物分生组织初始在到达繁殖阶段之前经历的 DNA 复制次数较多。因此，寿命长的品种会比寿命较短的品种经历更多的 DNA 复制，从而积累更多的突变。
Microsatellites, very short tandemly repeated DNA sequences, are being extensively used in evolutionary genetics and molecular breeding of crop plants, because of their high degree of allelic variability, which is presumably caused by a high rate of mutation that changes microsatellite array length. In humans and various animals, mutation rates vary greatly and fall within the range of 10–3to 10–6. In plants, the mutation rate at microsatellite loci seems to be higher than in animals, but no experimental estimates are available yet. Here, we report high spontaneous mutation rates (µ) and mutational bias at fifteen perfect (TAA)nmicrosatellite loci in inbred populations of chickpea. We show a significantly higher mutation rate, averaged across all loci, in the long-lived variety Ghab 2 (µ=1.0×10–2; detected in 16,050 allele-generations) compared to the variety Syrian Local (µ=3.9×10–3; detected in 15,600 allele-generations), which has a short life-span, with the majority of mutants (96.9%) in both varieties differing by ±1 repeat unit. Compared to animals, higher mutation rates in chickpea are likely to be due to the presence of long (TAA)nmicrosatellite repeat arrays and the larger number of DNA replications that meristematic initials of the plants undergo before reaching the reproductive phase. Thus, the long-lived variety undergoes more DNA replications, resulting in an accumulation of more mutations than in the variety with the shorter life-span.