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

ABSTRACT: 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 D

SUBMITTER: Poggio L 

PROVIDER: S-EPMC4152747 | biostudies-literature | 2014 Jun

REPOSITORIES: biostudies-literature