Genomic organization and evolution of alternative exons in a Drosophila calcium channel gene.
The genomic organization of a gene coding for an alpha 1 subunit of a voltage-gated calcium channel of Drosophila melanogaster (Dmca IA) was determined. Thirty-four exons, distributed over 45 kb of genomic sequence, have been identified and mapped, including exons in three regions involved in alternative splicing and new sites potentially involved in RNA editing. The comparison of the intron/exon boundaries of this channel with a mammalian counterpart shows that the genomic structure of these two genes has remained fairly similar during evolution, with more than half of the Drosophila intron positions being perfectly conserved compared to the human channel. Phylogenetic analysis of the mutually exclusive alternative exons revealed that they have diverged considerably. It is suggested that this divergence, rather than reflecting evolutionary age, is the likely result of accelerated rates of evolution following duplication.
Peixoto
A A
AA
Brandeis University, Department of Biology, Waltham, MA 02254-9110, USA. peixoto@binah.cc.brandeis.edu
Smith
L A
LA
Hall
J C
JC
D000595:Amino Acid Sequence; D000818:Animals; D015220:Calcium Channels / Q000235:genetics*; D020746:Calcium Channels, L-Type; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics*; D019143:Evolution, Molecular; D005091:Exons / Q000235:genetics*; D017344:Genes, Insect; D006801:Humans; D019476:Insect Proteins / Q000235:genetics*; D007438:Introns / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family; D009419:Nerve Tissue Proteins / Q000235:genetics; D010802:Phylogeny; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
C079146:CACNA1C protein, human; D015220:Calcium Channels; D020746:Calcium Channels, L-Type; D029721:Drosophila Proteins; D019476:Insect Proteins; D009419:Nerve Tissue Proteins; C472405:cac protein, Drosophila