Allele and haplotype diversity of X-chromosomal STRs in Ivory Coast.

Twenty-one X-chromosomal short tandem repeat (STR) loci, including the six clusters of linked markers DXS10148-DXS10135-DXS8378 (Xp22), DXS7132-DXS10079-DXS10074 (Xq12), DXS6801-DXS6809-DXS6789 (Xq21), DXS7424-DXS101 (Xq22), DXS10103-HPRTB-DXS10101 (Xq26), DXS8377-DXS10146-DXS10134-DXS7423 (Xq28) and the loci DXS6800, GATA172D05 and DXS10011 were typed in a population sample from Ivory Coast (n=125; 51 men and 74 women). Allele and haplotype frequencies as well as linkage disequilibrium data for kinship calculations are provided. On the whole, no significant differences in the genetic variability of X-STR markers were observed between Ivorians and other sub-Saharan African populations belonging to the Niger-Kordofanian linguistic group.

Beta-defensin 1 gene variability among non-human primates.

Defensins are a recently described family of peptides that play an important role in innate immunity. Recent studies have shown that defensins exhibit a broad spectrum of antimicrobial activities against bacteria and fungi. Three families have been identified so far in mammals, alpha-defensins, beta-defensins and theta-defensins, presumably derived from a common ancestral defensin. A long-term study on the evolution of these multigene families among primates has been undertaken to investigate: (1) the degree of interspecific differentiation; (2) the genetic mechanisms responsible for the variability of these molecules; and (3) the possible role of different environmental factors in their evolution. Nucleotide sequences have been obtained from great and lesser apes, several African and Asian catarrhine monkeys and one New World monkey. A comparison of rates of synonymous and nonsynonymous (amino-acid changing) nucleotide substitution indicates that the primate beta-defensin 1 gene evolved under a pattern of random nucleotide substitution as predicted by the neutral theory of molecular evolution. These results are not consistent with the hypothesis that the primate beta-defensin 1 gene has diversified in response to changes in the microbial species to which a given host is exposed. Analyses of interpecific variability have yielded some insights about the pattern of molecular evolution of the gene among primates. Humans and great apes present high levels of sequence similarity, differing in only one amino acid residue in the mature peptide. Compared with these taxa, hylobatids and cercopithecids exhibit 3-4 amino acid substitutions, some of which increase the net charge of the active molecule.

Nuclear ribosomal sequence analysis of Oidiodendron: towards a redefinition of ecologically relevant species.

• Nuclear ribosomal sequence analysis was performed to investigate delimitation of common Oidiodendron species comprising endomycorrhizal symbionts and close associates of ectomycorrhizal plants. • Neighbour-joining, maximum likelihood and parsimony analyses were used to compare 35 ribosomal DNA (internal transcribed spacer (ITS) and 5.8S) sequences (including sequences available in databases) from 15 putative species. • Oidiodendron citrinum formed a monophyletic group nested within O. maius, whereas O. tenuissimum and O. griseum did not appear either as distinct groups or as a single complex. Pairwise nucleotide divergence values between O. citrinum and O. maius were very low and comparable to intraspecific values obtained for both species; values for O. griseum and O. tenuissimum, although higher, overlapped those observed at the intraspecific level for the two species. • Molecular data indicate that O. maius and O. citrinum, which were described as distinct, though related species, could be moved to a subspecific level; however, the delimitation of O. griseum and O. tenuissimum is still open to question. Taxonomic rank assignment to groups determined from sequence data analysis is discussed.