Extensive, recent intron gains in Daphnia populations.

Academic Article


  • Rates and mechanisms of intron gain and loss have traditionally been inferred from alignments of highly conserved genes sampled from phylogenetically distant taxa. We report a population-genomic approach that detected 24 discordant intron/exon boundaries between the whole-genome sequences of two Daphnia pulex isolates. Sequencing of presence/absence loci across a collection of D. pulex isolates and outgroup Daphnia species shows that most polymorphisms are a consequence of recent gains, with parallel gains often occurring at the same locations in independent allelic lineages. More than half of the recent gains are associated with short sequence repeats, suggesting an origin via repair of staggered double-strand breaks. By comparing the allele-frequency spectrum of intron-gain alleles with that for derived single-base substitutions, we also provide evidence that newly arisen introns are intrinsically deleterious and tend to accumulate in population-genetic settings where random genetic drift is a relatively strong force.
  • Authors

  • Li, Wenli
  • Tucker, Abraham E
  • Sung, Way
  • Thomas, W. Kelley
  • Lynch, Michael
  • Status

    Publication Date

  • November 27, 2009
  • Published In

  • Science  Journal
  • Keywords

  • Alleles
  • Animals
  • Base Sequence
  • Computational Biology
  • DNA Breaks, Double-Stranded
  • DNA Repair
  • Daphnia
  • Exons
  • Genome
  • Introns
  • Molecular Sequence Data
  • Phylogeny
  • Polymorphism, Genetic
  • Polymorphism, Single Nucleotide
  • Repetitive Sequences, Nucleic Acid
  • Time Factors
  • Digital Object Identifier (doi)

    Start Page

  • 1260
  • End Page

  • 1262
  • Volume

  • 326
  • Issue

  • 5957