A phylogenetic analysis of indel dynamics in the cotton genus.

نویسندگان

  • Corrinne E Grover
  • Yeisoo Yu
  • Rod A Wing
  • Andrew H Paterson
  • Jonathan F Wendel
چکیده

Genome size evolution is a dynamic process involving counterbalancing mechanisms whose actions vary across lineages and over time. Whereas the primary mechanism of expansion, transposable element (TE) amplification, has been widely documented, the evolutionary dynamics of genome contraction have been less thoroughly explored. To evaluate the relative impact and evolutionary stability of the mechanisms that affect genome size, we conducted a phylogenetic analysis of indel rates for 2 genomic regions in 4 Gossypium genomes: the 2 coresident genomes (A(T) and D(T)) of tetraploid cotton and its model diploid progenitors, Gossypium arboreum (A) and Gossypium raimondii (D). We determined the rates of sequence gain or loss along each branch, partitioned by mechanism, and how these changed during species divergence. In general, there has been a propensity toward growth of the diploid genomes and contraction in the polyploid. Most of the size difference between the diploid species occurred prior to polyploid divergence and was largely attributable to TE amplification in the A/A(T) genome. After separating from the true parents of the polyploid genomes, both diploid genomes experienced slower sequence gain than in the ancestor, due to fewer TE insertions in the A genome and a combination of increased deletions and decreased TE insertions in the D genome. Both genomes of the polyploid displayed increased rates of deletion and decreased rates of insertion, leading to a rate of near stasis in D(T) and overall contraction in A(T) resulting in polyploid genome contraction. As expected, TE insertions contributed significantly to the genome size differences; however, intrastrand homologous recombination, although rare, had the most significant impact on the rate of deletion. Small indel data for the diploids suggest the possibility of a bias as the smaller genomes add less or delete more sequence through small indels than do the larger genomes, whereas data for the polyploid suggest increased sequence turnover in general (both as small deletions and small insertions). Illegitimate recombination, although not demonstrated to be a dominant mechanism of genome size change, was biased in the polyploid toward deletions, which may provide a partial explanation of polyploid genomic downsizing.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Chloroplast DNA Structural Variation, Phylogeny, and Age of Divergence among Diploid Cotton Species

The cotton genus (Gossypium spp.) contains 8 monophyletic diploid genome groups (A, B, C, D, E, F, G, K) and a single allotetraploid clade (AD). To gain insight into the phylogeny of Gossypium and molecular evolution of the chloroplast genome in this group, we performed a comparative analysis of 19 Gossypium chloroplast genomes, six reported here for the first time. Nucleotide distance in non-c...

متن کامل

Analysis of mitochondrial DNA sequences of Turcinoemacheilus genus (Nemacheilidae Cypriniformes) in Iran

Members of Nemacheilidae Family, Turcinoemacheilus genus were subjected to molecular phylogenetic analysis in this study. This genus was reported in 2009 to inhabit in Karoon River drainage, in contrary to previous assumption that it was the endemic species in the Basin of Tigris River. It was sampled from three stations placed in different tributaries in Karoon drainage and evaluated to unders...

متن کامل

Analysis of mitochondrial DNA sequences of Turcinoemacheilus genus (Nemacheilidae Cypriniformes) in Iran

Members of Nemacheilidae Family, Turcinoemacheilus genus were subjected to molecular phylogenetic analysis in this study. This genus was reported in 2009 to inhabit in Karoon River drainage, in contrary to previous assumption that it was the endemic species in the Basin of Tigris River. It was sampled from three stations placed in different tributaries in Karoon drainage and evaluated to unders...

متن کامل

Assessment of relationships between Iranian Fritillaria (Liliaceae) Species Using Chloroplast trnh-psba Sequences and Morphological Characters

The genus Fritillaria comprises of 165 taxa of medicinal, ornamental and horticultural importance. Evolutionary relationships in this genus is an interesting research area, attracting many researchers. In this study, phylogenetic relationships among 18 native to endemic species in Iran belonging to four subgenera Petilium, Theresia, Rhinopetalum and Fritillaria, are assessed using chloroplast t...

متن کامل

Development of INDEL markers to discriminate all genome types rapidly in the genus Oryza

The wild Oryza species are rich in genetic diversity and are good resources for modern breeding of rice varieties. The reliable ex situ conservation of various genetic resources supports both basic and applied rice research. For this purpose, we developed PCR-based and co-dominant insertion/deletion (INDEL) markers which enable the discrimination of the genome types or species in the genus Oryz...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Molecular biology and evolution

دوره 25 7  شماره 

صفحات  -

تاریخ انتشار 2008