Homogenization of geographical variants at the nontranscribed spacer of rDNA in Drosophila mercatorum |
| |
Authors: | Williams SM; DeSalle R; Strobeck C |
| |
Institution: | Department of Genetics, University of Alberta, Edmonton, Canada. |
| |
Abstract: | rDNA nontranscribed spacer (NTS) lengths of Drosophila mercatorum have been
measured in individuals from several geographic regions. Individuals from
the different geographic subpopulations share some length fragments but are
in general distinct. The length differences, both within and between
individuals, arise from different copy numbers of a 250-bp repeating unit
that is localized to one part of the NTS. In addition to the length
differences caused by the 250-bp repeat, there is a Y chromosome
(male)-specific length variant elsewhere in the NTS that is approximately
70 bp shorter than the NTS fragment from the X chromosome. Sexual
dimorphism seems to be present in all Drosophila. Also, D. mercatorum has
fewer NTS length variants per individual than does D. melanogaster while
possessing comparable levels of restriction- site polymorphism. The
mechanisms that may cause this pattern of variation are selection, gene
conversion, and unequal recombination.
|
| |
Keywords: | |
本文献已被 Oxford 等数据库收录! |
|