Frequencies of Second and Third Chromosome Lethals in a Tropical Population of Drosophila melanogaster

Abstract

Ninety-five genome (2nd and 3rd chromosomes tested simultaneously) lethals were recovered from 119 tests of material caught near Bogota, Colombia. Eighty-six of 89 lethals tested were located as follows: 18 on the 2nd, 31 on the third, and 37 on both the 2nd and the 3rd. The remaining 3 genome lethals were caused by combinations of 2nd and 3rd chromosomes. Of the lethals which were located on definite chromosomes, 55 were on the 2nd and 68 were on the 3rd; this does not differ significantly from a 1:1 distribution. The frequencies of 2nd and 3rd chromosome lethals in this population appear to be approximately 55%.