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Variation on the Y chromosome may permit our understanding the evolution of the human paternal lineage and male gene flow. This study reports upon the distribution and non random association of alleles at four Y-chromosome specific loci in four populations, three Caucasoid (Italian, Greek and Slav) and one Asian. The markers include insertion/deletion (p12f), point mutation (92R7 and pY alpha I), and repeat sequence (p21A1) polymorphisms. Our data confirm that the p12f/TaqI 8 kb allele is a Caucasoid marker and that Asians are monomorphic at three of the loci (p12f, 92R7, and pY alpha I). The alleles at 92R7 and pY alpha I were found to be in complete disequilibrium in Europeans. Y-haplotype diversity was highly significant between Asians and all three European groups (P < 0.001), but the Greeks and Italians were also significantly different with respect to some alleles and haplotypes (P < 0.02). We find strong evidence that the p12f/TaqI 8 kb allele may have arisen only once, as a deletion event, and, additionally, that the present-day frequency distribution of Y chromosomes carrying the p12f/8 kb allele suggests that it may have been spread by colonising sea-faring peoples from the Near East, possibly the Phoenicians, rather than by expansion of Neolithic farmers into continental Europe. The p12f deletion is the key marker of a unique Y chromosome, found only in Caucasians to date, labelled 'Mediterranean' and this further increases the level of Y-chromosome diversity seen among Caucasoids when compared to the other major population groups.

The distribution of two common TaqI restriction fragment length polymorphisms (RFLPs) of the cholesteryl ester transfer protein (CETP) gene were determined in 271 Italian-born and 170 Greek-born migrants to Melbourne, Australia. A much smaller number were examined for the EcoNI RFLP of the same gene. Allele frequencies of the TaqI A RFLP exhibited the least variation in both ethnic groups, and no significant regional heterogeneity in allele or genotype frequencies of either TaqI RFLP was detected for Greece or Italy. There was no difference between Italians and Greeks for the TaqI A polymorphism and the variability at the B RFLP was of borderline significance. Comparisons with other Caucasian populations revealed that allele frequencies of all three CETP RFLPs are remarkably uniform within Caucasians, with the TaqI B polymorphism being the most variable.

The relation between TaqI restriction fragment length polymorphisms (RFLPs) of the cholesteryl ester transfer protein (CETP) gene and plasma lipid and lipoprotein phenotypes was investigated in a sample of Italian and Greek migrants of both sexes, age 40-69 years. Italians display significantly higher mean triglyceride and lower mean high-density lipoprotein (HDL) cholesterol levels than Greeks. Greek females have significantly higher HDL cholesterol than Greek males, and Italian females have significantly higher low-density lipoprotein (LDL), HDL, and total cholesterol than Italian males. The differences in RFLP allele frequencies between the two ethnic groups and sexes are insignificant. Multivariate analyses show that in the Greek sample the TaqI B RFLP of the CETP gene has a highly significant effect on HDL cholesterol levels regardless of sex and that the TaqI A polymorphism has a significant effect on HDL levels in females but modulates LDL cholesterol concentrations in males. Among Italians, with the sexes considered separately or combined, no such effects of the CETP TaqI polymorphisms are detected. Kruskal-Wallis tests detected associations between the TaqI B polymorphism in all Greek samples but not in the Italian samples. Genotype CETP*B2 exhibits significantly higher HDL cholesterol concentrations than either of the other two TaqI B genotypes, but there is no evidence of a dosage effect of the *B2 allele. These data suggest that associations between the CETP gene and lipid phenotypes can be population specific. Further, they suggest that such associations are mediated in some way by gender.

The part of the Y chromosome not involved in recombination has been found to exhibit an extremely low frequency of DNA restriction fragment length polymorphisms (RFLPs) compared with either the X chromosome or autosomes. Also, the few Y-chromosome-specific RFLPs that have been identified have rarely been examined in more than one population. In this study two Y-chromosome-specific RFLPs at loci DYS11 and DYZ8 are examined in Italian and Greek migrants to Australia. The frequency of the rarer (8.5-kb) TaqI allele at DYS11 was 21% in Italians and even greater (34%) in Greeks. There is an inverse relationship between the frequency of the 8.5-kb allele and latitude on the Italian mainland; the regional variation (based on subject's birthplace in Italy) was significant (p < 0.01). The incidence of the 8.5-kb allele in southern Italy may reflect Greek colonization during pre-Roman times when this region was part of Magna Graecia. The frequency of the variant TaqI allele (7, 4 kb) at the DYZ8 locus is much higher in both Greeks and Italians (31% in each) than in Germans (5%), the only previously examined population. DYZ8 shows considerably less variation than DYS11 across the regional divisions of both Greece and Italy. The present findings, when added to the few other data available, indicate that these two Y-chromosome-specific loci are useful markers for investigating population affinities through the paternal line. Also, heterogeneity at these two loci (and added to that at the DYS1 locus) suggests that Mediterranean populations, compared with other groups, exhibit a high level of diversity of Y-chromosome-specific RFLPs.

Restriction fragment length polymorphisms detected by the cDNA probe, pEMBL36, at the CALCA locus (calcitonin gene and calcitonin gene related peptide) on TaqI blots were examined in samples from Italian, Greek and Vietnamese migrants to Melbourne, Australia and in a sample of residents from the island of Tasmania, Australia. The frequency of the rarer of the two alleles of this polymorphism, A2 (8.0kb) varied between a low of 6% in Vietnamese to a maximum of 38% in Tasmanians. The frequency range of the A2 allele in European populations, however, was considerably less. Analysis revealed no significant heterogeneity for this polymorphism among either the European or European derived populations, and these combined data exhibited a frequency of 33% for the A2 allele. Though based on a very small Vietnamese sample this study suggests that the A2 allele is less frequent in those of Asian ancestry.