MOLECULAR VARIATION FOR mtDNA HAPLOTYPES OF Drosophila melanogaster AND D. simulans NATURAL POPULATIONS BASED ON MORE ACCURATE RESTRICTION-SITE MAP

Four restriction enzymes; Hae III, Msp I (4·base cutters), Pvu II and Sail (6-
base cutters), were used to reconstruct restriction-site map, with better resolution, for
the mtDNA from nine geographically different natural populations of D. me/anogaster
and D. simulans. A total of 32 restriction sites were scored for mtDNA haplotypes; 24
sites of them were from D. melanogaster and the remaining eight sites were from D.
simulans. Five restriction sites were found to be shared between the two species. Six
fragment patterns were scored for each of Hae III and Msp I and two fragment
patterns were scored for each of Pvu II and Sal I. In D. simulans, only one fragment
pattern was scored for each of the four restriction enzymes. Eight sites (Hae III, 0.8,
Msp I, 1.0, Pvu I, 4.1, 7.1 and 11.0, and Sal 1,2.0, 7.0 and 14.8) were detected in all
D. melanogaster mtDNA haplotypes and were considered to be monomorphic. The
highest estimate of polymorphism (94.29%) was detected for each of the two sites of
Hae III, 4.4 and 10.6. The highest significant estimates of polymorphism were
recorded for each of Alexandria (0.0356::0.0012), Baltim (0.0344::0.0), sent-sueet
(0.0338±0.0018), and Assiut (0.0325::0.023) haplotypes. The lowest estimate of
polymorphism was recorded for Sallom haplotypes (0.1250±0.0). The highest estimate
of heterozygosity (H) was recorded for Alexandria haplotype (0.0230::0.0134). The net
nucleotide divergence rates (dA) ranged from 0.0014 (between the two D. simulans
haplotypes) to 0.1415 (between Ismailia, D. simulans and Alexandria, D.
melanogaster). The highest estimates of (dA) between D. melanogaster haplotypes
were recorded between Sallom and each of Beni-Sueef (0.0509) and Assiut (0.0504).
Both methods of phylogenetic tree, UPGMA and NJ joined together the .two
populations of D. simulans in one cluster apart from D. me/anogaster with a branch
length equal to 0.1263. The NJ tree used Assiut population as a root. There were fifty
cases (10 significant and 40 highly significant) of disequilibria between the 496
combinations of the 32 scored sites with percentage of 10.08%.