ISSN:
1432-1432
Keywords:
HawaiianDrosophila
;
Yolk protein genes
;
Trinucleotide repeats
;
Nucleotide length mutations
;
Nucleotide insertions/deletions
;
Replication slippage
;
Founder effects
;
Genetic hitchhiking
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Nucleotide sequence analysis has demonstrated that interspecific size variation in the YP2 yolk protein among HawaiianDrosophila is due to in-frame insertions and deletions in two repetitive segments of the coding region of the Yp2 gene. Sequence comparisons of the complex repetitive region close to the 5′ end of this gene across 34 endemic Hawaiian taxa revealed five length morphs, spanning a length difference of 21 nucleotides (nt). A phylogenetic character reconstruction of the length mutations on an independently derived molecular phylogeny showed clade-specific length variants arising from six ancient events: two identical insertions of 6 nt, and four deletions, one of 6 nt, one of 12 nt, and two identical but independent deletions of 15 nt. These mutations can be attributed to replication slippage with nontandem trinucleotide repeats playing a major role in the slipped-strand mispairing. Geographic analysis suggests that the 15 nt deletion which distinguishes theplanitibia subgroup from thecyrtoloma subgroup occurred on Oahu about 3 million years ago. The homoplasies observed caution against relying too heavily on nucleotide insertions/deletions for phylogenetic inference. In contrast to the extensive repeat polymorphisms within otherDrosophila and the human species, the more complex 5′Yp2 repetitive region analyzed here appears to lack polymorphism among HawaiianDrosophila, perhaps due to founder effects, low population sizes, and hitchhiking effects of selection on the immediately adjacent 5′ region.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02337356
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