Identification of hepatitis B virus genome in faecal sample from wild living chimpanzee (Pan troglodytes troglodytes) in Gabon.

Non-invasive faecal sampling in the equatorial forest in Gabon allowed the first identification of the hepatitis B virus (HBV-Ch(RC170)) genome in samples collected from wild chimpanzees (Pan troglodytes troglodytes). The HBV-Ch(RCl70)sequence clustered with 100% bootstrap support with previous viral sequences obtained from Pan troglodytes subspecies. This is the first evidence of HBV infection in wild apes and confirms that the HBV-like strains thus far characterized in captive apes are directly related to those circulating in the wild.

Two distinct STLV-1 subtypes infecting Mandrillus sphinx follow the geographic distribution of their hosts.

The mandrill (Mandrillus sphinx) has been shown to be infected with an STLV-1 closely related to HTLV-1. Two distinct STLV-1 subtypes (D and F) infect wild mandrills with high overall prevalence (27.0%) but are different with respect to their phylogenetic relationship and parallel to the mandrills' geographic range. The clustering of these new STLV-1mnd sequences with HTLV-1 subtype D and F suggests first, past simian-to-human transmissions in Central Africa and second, that species barriers are easier to cross over than geographic barriers.

Molecular evidence for deep phylogenetic divergence in Mandrillus sphinx.

Mandrills (Mandrillus sphinx) are forest primates indigenous to western central Africa. Phylogenetic analysis of 267 base pairs (bp) of the cytochrome b gene from 53 mandrills of known and 17 of unknown provenance revealed two phylogeographical groups, with haplotypes differentiated by 2.6% comprising seven synonymous transitions. The distribution of the haplotypes suggests that the Ogooué River, Gabon, which bisects their range, separates mandrill populations in Cameroon and northern Gabon from those in southern Gabon. The haplotype distribution is also concordant with that of two known mandrill simian immunodeficiency viruses, suggesting that these two mandrill phylogroups have followed different evolutionary trajectories since separation.

Multiplex DNA typing of short-tandem-repeat loci on the Y chromosome.

To facilitate evolutionary and forensic studies of DNA polymorphisms on the Y chromosome, we devised a multiplex amplification procedure for short-tandem-repeat (STR) loci. Four tetranucleotide STR loci (DYS19, DYS390, DYS391, and DYS393) were simultaneously amplified with FAM-labeled primers and genotypes were determined with an automated DNA sequencer. We typed 162 males from three U.S. populations (African-Americans, European-Americans and Hispanics) and found that the haplotype diversities range from 0.920 to 0.969. This quadruplex system provides a facile means of genotyping these Y chromosome STRs, and should be useful in population genetic and forensic applications.

Racial disparity in overexpression of the p53 tumor suppressor gene in stage I endometrial cancer.

OBJECTIVE: This study was conducted to determine whether overexpression of the p53 tumor suppressor gene is associated with poor outcome in early-stage endometrial cancers and whether a racial difference in the frequency of p53 overexpression contributes to the observed racial disparity in survival rates. STUDY DESIGN: Immunostaining for the p53 gene was performed in 164 women with stage I endometrial adenocarcinomas. RESULTS: Overexpression of mutant p53 protein was seen in 28 out of 164 (17%) cases and was associated with a poor histologic grade (p = 0.003) and a nonendometrioid histologic appearance (p = 0.06). Overexpression also was three times more frequent in blacks (15 out of 44, 34%) than in whites (13 out of 117, 11%) (p = 0.003). Recurrent disease developed in 15 out of 164 (9%) cases and was more than twice as frequent in cases when the p53 gene was overexpressed (5 out of 28, 18%) than in cases with normal expression (10 out of 136, 7%). Recurrent disease was seen in 6 out of 44 (14%) blacks compared to 9 out of 117 (8%) whites. CONCLUSIONS: These data support the hypothesis that differences in the frequency of alteration of the p53 tumor suppressor gene contribute to the racial disparity in endometrial cancer survival.

Alu insertion polymorphisms and human evolution: evidence for a larger population size in Africa.

Alu insertion polymorphisms (polymorphisms consisting of the presence/absence of an Alu element at a particular chromosomal location) offer several advantages over other nuclear DNA polymorphisms for human evolution studies. First, they are typed by rapid, simple, PCR-based assays; second, they are stable polymorphisms-newly inserted Alu elements rarely undergo deletion; third, the presence of an Alu element represents identity by descent-the probability that different Alu elements would independently insert into the exact same chromosomal location is negligible; and fourth, the ancestral state is known with certainty to be the absence of an Alu element. We report here a study of 8 loci in 1500 individuals from 34 worldwide populations. African populations exhibit the most between-population differentiation, and the population tree is rooted in Africa; moreover, the estimated effective time of separation of African versus non-African populations is 137,000 +/- 15,000 years ago, in accordance with other genetic data. However, a principal coordinates analysis indicates that populations from Sahul (Australia and New Guinea) are nearly as close to the hypothetical ancestor as are African populations, suggesting that there was an early expansion of tropical populations of our species. An analysis of heterozygosity versus genetic distance suggests that African populations have had a larger effective population size than non-African populations. Overall, these results support the African origin of modern humans in that an earlier expansion of the ancestors of African populations is indicated.