Unequal Accumulation Of Nucleotide Diversity In The Two Co-Resident Genomes Of Allopolyploid Cotton - Université de Rennes Accéder directement au contenu
Communication Dans Un Congrès Année : 2013

Unequal Accumulation Of Nucleotide Diversity In The Two Co-Resident Genomes Of Allopolyploid Cotton

Résumé

Rates of molecular evolution are highly variable within and among genes and among lineages. The forces responsible for this variation include a suite of internal genomic mechanisms (e.g., recombinational environment, repair efficiency) and external population level phenomena (e.g., selection, effective population size). A promising model for disentangling intrinsic and extrinsic forces are allopolyploid plants, which combine two (or more) set of homoeologous genes in a single nucleus and in the same ecological context. Thus, the null hypothesis may be tested that homoeologs will accumulate nucleotide diversity at equivalent rates in a set of populations within a species. Here we test this hypothesis using Gossypium hirsutum (cotton), a natural allopolyploid derived from the merger, 1-2 million years ago (MYA) of progenitor diploid genomes (A and D), which diverged from a common ancestor ~5-10 million years ago. Homoeologous chromosomes in the allopolyploid (AT and DtT remain highly similar to those of their diploid orthologs, with high synteny and colinearity. Using sequence capture and 454 sequencing, we screened 40 diverse G. hirsutum accessions, targeting exonic regions in ~400 homoeologous gene pairs. Analyzed sequences included approximately twice the target space, due to recovery of introns and flanking UTRs. Nucleotide diversity levels in G. hirsutum are low, consistent with earlier indications. Notwithstanding this low level of overall diversity, preliminary analyses suggest that diversity is higher in the At genome than the Dt genome, genome-wide. This enhanced diversity may reflect differences related to the two-fold difference in progenitor genome size. Our results demonstrate that genic environment plays a key role in the genesis of genetic novelty, and how allopolyploidy can create novel allelic combinations with the potential for adaptive traits.
Fichier non déposé

Dates et versions

hal-01594749 , version 1 (26-09-2017)

Identifiants

  • HAL Id : hal-01594749 , version 1
  • PRODINRA : 391760

Citer

Emmanuel Szadkowski, Justin T. Page, Josh A. Udall, J.A. Jeddeloh, Corrinne E. Grover, et al.. Unequal Accumulation Of Nucleotide Diversity In The Two Co-Resident Genomes Of Allopolyploid Cotton. Plant and Animal Genomes Conference, Jan 2013, San Diego, United States. ⟨hal-01594749⟩
60 Consultations
0 Téléchargements

Partager

Gmail Facebook X LinkedIn More