Rates of DNA evolution in Drosophila depend on function and developmental stage of expression.
DNA-sequence divergence of genes expressed in the embryonic stage was compared with the divergence of genes expressed in adults for 13 species of Drosophila representing various degrees of relatedness. DNA-DNA hybridization experiments were conducted using as tracers complementary DNA (cDNA) reversed transcribed from poly(A)+ mRNA isolated from different developmental stages. The results indicate: (1) cDNA is less diverged than total single-copy DNA; (2) cDNA sequences are not in the rapidly evolving fraction of the single-copy genome of Drosophila; (3) early in evolutionary divergence embryonic messages are about half as diverged as adult messages; sequence data from some of the species compared indicate this is likely due to differences in rates of silent substitutions in genes expressed at different stages of development; and (4) at greater evolutionary distance, the differences in embryonic and adult messages disappear; this could be due to lineage-specific shifts in codon usage.
Powell
J R
JR
Department of Biology, Yale University, New Haven, Connecticut 06511.
Caccone
A
A
Gleason
J M
JM
Nigro
L
L
D000818:Animals; D004247:DNA / Q000235:genetics*; D004330:Drosophila / Q000196:embryology / Q000235:genetics*; D005314:Embryonic and Fetal Development / Q000235:genetics; D009154:Mutation; D009693:Nucleic Acid Hybridization; D010802:Phylogeny; D011061:Poly A / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D013045:Species Specificity
D012333:RNA, Messenger; D011061:Poly A; D004247:DNA