Analysis of the C4 genes in baleen whales using a human cDNA probe

Abstract

We have used a human C4 cDNA probe to investigate the complement component C4 gene in four members of the family Balaenopteridae: fin whale (Balaenoptera physalus), sei whale (B. borealis), minke whale (B. acutorostrata), and bryde's whale (B. edeni). Restriction mapping of genomic DNA from the first three species suggests the presence of only one locus in these species, and also shows that the C4 genes in the three species are very similar. We have used 14 restriction endonucleases to investigate the restriction fragment length polymorphism (RFLP) of fin whales, 13 enzymes for sei whales, and 8 enzymes for the minke whale. No polymorphism was seen in DNA from the five minke whale samples, but Rsa I and Taq I restriction enzymes gave polymorphism in fin and sei whales whereas Hind III and Msp I restriction enzymes showed polymorphism in sei whales only. Only one bryde's whale sample was available for investigation. The study of DNA available from mother-fetus pairs from the two polymorphic species demonstrated a simple, two-allele transmission of RFLP alleles.

Mechanism and consequences of the duplication of the human C4/P450c21/gene X locus.

“…This suggests that the human and murine duplications arose independently, postdating mammalian speciation. Independent duplication of the C4/P45Oc21/X locus in various mammalian genomes might explain the differences in the spacing between C4 and P450c21 in the murine, bovine, and human genomes and the apparent presence of single C4/P450c21/X clusters in some other incompetely studied mammalian species (18,29,55). However, the data cannot distinguish postspeciation duplications in some mammalian lineages from a prespeciation duplication followed by postspeciation genetic losses in some lineages.…”

“…Also, 40 kb of DNA separates the 3' end of the mouse P450c21A gene from the 5' end of the mouse C4B gene (57), while only 6.5 kb separates the corresponding human genes. Finally, pigs (18), whales (55), Syrian hamsters, and possibly guinea pigs (29) appear to have only one P450c21 gene, suggesting that this locus may have duplicated independently in cattle, mice, and humans after mammalian speciation.…”

Limited MHC polymorphism in the southern elephant seal: implications for MHC evolution and marine mammal population biology

“…the Gir Forest lion, South African cheetah, East African cheetah, and Ngorongoro C rater lion) is accom panied by low allozyme heterozygosity indicative of population bottlenecks (see Yuhki & O 'Brien 1990). For the fin and sei whales, the specificity of low mhc polymorphism is also shown by the finding of a considerable am ount of w ithin-population variation in the com plem ent com ponent C4 gene (Spilliaert et al 1990). In mice and hum ans, this locus is found within the mhc region, and shows relatively high polym orphism (Klein 1986, chapter 9).…”

Twin genes and endocrine disease: CYP21 and CYP11B genes

“…Other mamma¬ lia seem to possess single 21-hydroxylase and C4 genes, e.g. whale (25), horse (26), Syrian hamster, guinea pig (22) and cat (27). These findings can be interpreted in two ways: (i) Several independent duplication events occurring in different mammalian lineages, a concept supported by the fact that CYP21 nucleotide sequence homology within a species (>95%) considerably exceeds that between species (about 80%) in species with a duplicated CYP21 locus.…”