...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Theoretical Biology >Cytological, Genetic and Evolutionary Functions of Chiasmata Based on Chiasma Graph Analysis
【24h】

Cytological, Genetic and Evolutionary Functions of Chiasmata Based on Chiasma Graph Analysis

机译：基于Chiasma图分析的Chiasmata的细胞学，遗传和进化功能

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The nature of the chiasma as a cytological parameter for analysing cross-over was reexamined quantitatively by an improved chiasma graph method. It was reconfirmed in Mus platythrix (n =13) that interstitial chiasmata at diakinesis are distributed randomly and almost uniformly along bivalents except for the centromere and telomere regions. The size of these chiasma blank regions was consistently 0.8% of the total length of haploid autosomes in all chromosomes. There was a minimum value of chiasma interference distance between two adjacent chiasmata, which was constantly 1.8% in all chromosomes. The chiasma frequency at diakinesis was 20.1 plus or minus 2.0 by the conventional method including terminal chiasmata. However, the primed in situ labeling technique revealed that terminal chiasmata were mostly telomere-telomere associations. From these data and also from recent molecular data we concluded that the terminal chiasma is cytologically functional for ensuring the normal disjunction of bivalents at anaphase I, but genetically non-functional for shuffling genes. The chiasma frequency excluding terminal chiasmata was 14.6 plus or minus 1.8. Reexamination of the chiasma frequency of 106 animal species revealed that the chiasma frequency increased linearly in proportion to the haploid chromosome number in spite of remarkable difference in their genome size. The increase in chiasma frequency would be evolution-adaptive, because gene shuffling is expected to be accelerated in species with high chromosome numbers.
机译：通过改进的chiasma图法定量地检查了chiasma作为分析交叉的细胞学参数的性质。鸭嘴兽（n = 13）中再次证实，运动异常的间质性散光在着丝粒和端粒区域以外沿二价随机且几乎均匀地分布。在所有染色体中，这些chiasma空白区域的大小始终是单倍体常染色体总长度的0.8％。两个相邻视交叉之间的视交叉干扰距离最小值，在所有染色体中始终为1.8％。采用包括终末眼裂的常规方法，运动异常时的裂as发生频率为20.1正负2.0。然而，灌注的原位标记技术显示终末眼裂主要是端粒-端粒缔合。从这些数据以及最近的分子数据，我们得出结论，终末as裂在细胞内具有功能，以确保在后期I时二价的正常分离，但在遗传上对改组基因不起作用。不包括终末视交叉的横断面频率为14.6正负1.8。对106种动物的chiasma频率进行的重新检查显示，尽管其基因组大小存在显着差异，但chiasma频率却与单倍体染色体数成线性比例增加。由于预期在具有高染色体数的物种中基因改组将加速，因此裂as频率的增加将是适应进化的。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号