• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>AoB PLANTS >Genome downsizing and karyotype constancy in diploid and polyploid congeners: a model of genome size variation
【24h】

Genome downsizing and karyotype constancy in diploid and polyploid congeners: a model of genome size variation

机译：二倍体和多倍体同源基因的基因组缩减和核型恒定性：基因组大小变异的模型

获取原文
       
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Evolutionary chromosome change involves significant variation in DNA amount in diploids and genome downsizing in polyploids. Genome size and karyotype parameters of Hippeastrum species with different ploidy level were analysed. In Hippeastrum, polyploid species show less DNA content per basic genome than diploid species. The rate of variation is lower at higher ploidy levels. All the species have a basic number x = 11 and bimodal karyotypes. The basic karyotypes consist of four short metacentric chromosomes and seven large chromosomes (submetacentric and subtelocentric). The bimodal karyotype is preserved maintaining the relative proportions of members of the haploid chromosome set, even in the presence of genome downsizing. The constancy of the karyotype is maintained because changes in DNA amount are proportional to the length of the whole-chromosome complement and vary independently in the long and short sets of chromosomes. This karyotype constancy in taxa of Hippeastrum with different genome size and ploidy level indicates that the distribution of extra DNA within the complement is not at random and suggests the presence of mechanisms selecting for constancy, or against changes, in karyotype morphology.
机译：进化染色体的改变涉及二倍体中DNA量的显着变化和多倍体中基因组的缩小。分析了不同倍性水平的朱顶红种的基因组大小和核型参数。在Hippeastrum中，多倍体物种每个基本基因组的DNA含量要少于二倍体物种。在较高的倍性水平下变异率较低。所有的物种都有一个基本数x = 11和双峰核型。基本的核型由四个短的亚中心染色体和七个大的染色体（亚亚中心和亚亚中心）组成。即使存在基因组缩小的情况下，双峰核型仍保持单倍染色体组成员的相对比例。保持核型的恒定性是因为DNA量的变化与全染色体补体的长度成正比，并且在长短染色体组中独立变化。具有不同基因组大小和倍性水平的朱顶红属类群中的这种核型恒定性表明，补体中额外DNA的分布不是随机的，这表明存在选择恒定或抵抗变化的机制的核型形态。

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