Further genetic studies on the Katsunuma population of Drosophila melanogaster

Citation
Y. Hatano et al., Further genetic studies on the Katsunuma population of Drosophila melanogaster, GENE GEN SY, 74(5), 1999, pp. 219-225
Citations number
42
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biology,"Molecular Biology & Genetics
Journal title
GENES & GENETIC SYSTEMS
ISSN journal
1341-7568 → ACNP
Volume
74
Issue
5
Year of publication
1999
Pages
219 - 225
Database
ISI
SICI code
1341-7568(199910)74:5<219:FGSOTK>2.0.ZU;2-5
Abstract
Changes in the genetic structure of the Katsunuma natural population of Dro sophila melanogaster have been examined during the past 35 years. The frequ ency of recessive lethal genes on the second chromosome once increased from 15% to 30% in the early 1970s, then decreased to about 24% in the late 197 0s, and thereafter showed no significant changes. Sterility genes, the freq uency of which is always less than the lethals, showed a similar tendency. The SD (segregation distorter) mutant gene disappeared but some others such as rbl (reduced bristle) and bw (brown) persisted in the population. The f requency of inversion-carrying chromosomes gradually decreased in the perio d, such that the standard chromosome frequency in the second and third chro mosomes increased from about 40% to more than 80%. Coincident with these fr equency changes is the invasion of a transposable element P into the Katsun uma population. The P element should have invaded into Katsunuma in the lat e 1960s. It spread over the population apparently inducing deleterious muta tions, causing the decrease in the allelism rate, and hence increasing the effective population size. Soon, however, most flies became resistant to th e P element-mediated transposition as they began to harbor defective P elem ents. During the course of spreading, the P element must also have induced deleterious mutations on the polymorphic inversions, breaking up the hetero tic gene complexes along the chromosomes, which probably caused the reducti on in the frequency of inversion chromosomes. Temporal invasion of D. simul ans, a sibling species of D. melanogaster, into Katsunuma occurred several times after 1978, and the species seems to have been settled since 1990. Th is, however, did not have any effect on the genetic structure of D. melanog aster population.