Characterization of newly gained introns in Daphnia populations.
Bottom Line: A disproportionally large number of new introns were found in historically isolated populations in Oregon.A majority (55/90 or 61.1%) of the identified neointrons have associated internal direct repeats with lengths and compositions that are unlikely to occur by chance, suggesting repeated bouts of staggered double-strand breaks (DSBs) during their evolution.Accordingly, internal, staggered DSBs may contribute to a passive trend toward increased length and sequence diversity in nascent introns.
Affiliation: Department of Pediatrics, Section of Genomic Pediatrics, Medical College of Wisconsin email@example.com.Show MeSH
Mentions: Distributions of derived intron-bearing alleles that are still segregating in D. pulex clones are divided into three categories: overall, Oregon, and parallel gains (fig. 2). Our estimate for the average age of all derived intron-bearing alleles that are polymorphic in D. pulex (overall) is 1.40 ± 0.09 × 105 (mean ± SE) years. D. pulex populations in Oregon were thought to have experienced one or more historical bottleneck events (Lynch et al. 1999). Thus, the age estimates of clades formed by derived intron-bearing alleles that are specific to Oregon can potentially provide insights into the historical events associated with new intron gains restricted to this geographic area. Our estimate for the average age of new introns endemic to Oregon populations (Oregon gain) is 1.20 ± 0.09 × 105 (mean ± SE) years.Fig. 2.—
Affiliation: Department of Pediatrics, Section of Genomic Pediatrics, Medical College of Wisconsin firstname.lastname@example.org.