TITLE:
Further evidence for the theory that crossover interference in Drosophila melanogaster is dependent on genetic rather than physical distance between adjacent crossover points
AUTHORS:
Petter Portin
KEYWORDS:
Chiasma; Chromosome; Map Length; Meiosis
JOURNAL NAME:
Open Journal of Genetics,
Vol.3 No.2,
June
25,
2013
ABSTRACT:
The effect of heat shock on certain meiotic parameters
in Drosophila melanogaster was
studied in the cv – v – f region of the X chromosome of females homozygous for the mus309 mutation, deficient in DNA double-strand
break repair, or those of wild type. The heat shock in the wild females caused
the frequencies of the single crossovers and double crossovers and all the map
lengths to decrease while crossover interference remained unchanged. In the mus309 mutants all
parameters, crossover interference included, remained unchanged despite the
heat shock treatment. However, the mus309 mutation had a significant effect on all meiotic parameters both
in the females not given the heat shock and in the heat shocked females with
the exception that the recombination frequency of the v and f markers was the
same in both genotypes in the females not given the heat shock. It seems that
the heat shock treatment has an effect on crossing over which is independent on
the mus309 gene and affecting
the occurrence of crossing over itself. On the other hand, the mus309 gene has an effect
on crossing over which is independent of the heat shock treatment and affects
some precondition of crossing over. This precondition is probably the choice
between two routes of the repair of double-strand DNA breaks known to be
controlled by the mus309 gene. As explained in the discussion, the results are in accordance with the genetic models of interference in
which interference depends on genetic distance between the crossover points,
but in contradiction with physical models where interference is dependent on
physical distance between the crossover points.