The gene profile of Arabic-speaking Moroccans has been compared with those of other Mediterranean populations in order to provide additional information about the history of their origins. Our HLA data suggest that most Moroccans are of a Berber (Imazighen) origin and that Arabs who invaded North Africa and Spain in the 7th century A.D. did not substantially contributed to the gene pool; however, they imposed their advanced culture and their religion. Present-day Egyptians are also related to Moroccan Berbers and this supports an ancient Saharan origin for part of the present-day Mediterraneans, particularly for the Arabic-speaking ones (also Algerians) and also for the older substratum of Mediterranean people.

The Cretan HLA gene profile has been compared with those of other Mediterranean populations in order to provide additional information regarding the history of their origins. The allele frequencies, genetic distances between populations, relatedness dendrograms and correspondence analyses were calculated. Our results indicate that the Indoeuropean Greeks may be considered as a Mediterranean population of a more recent origin (after 2000 B.C.), while all other studied Mediterraneans (including Cretans) belong to an older substratum which was present in the area since pre-Neolithic times. A significant Turkish gene flow has not been detected in the Greek or Cretan populations, although Greeks and Turks have two high frequency HLA-DRB-DQB haplotypes in common. It is proposed that Imazighen (Caucasoid Berbers living at present in the North African coast and Saharan areas) are the remains of pre-Neolithic Saharan populations which could emigrate northwards between about 8000-6000 B.C., when desert desiccation began. They also could be part of the stock that gave rise to Sumerians, Cretans and Iberians; this is supported by both linguistic and HLA genetic data.

The HLA allele frequency distribution of the Mexican Mazatecan Indians (Olmec culture) has been studied and compared with those of other First American Natives and worldwide populations (a total of 12,100 chromosomes; 6,050 individuals from 59 different populations). The main conclusions are: 1) An indirect evidence of Olmec and Mayan relatedness is suggested, further supporting the notion that Olmecs may have been the precursors of Mayans; 2) Language and genetics do not completely correlate in microenvironmental studies; and 3) Peopling of the Americas was probably more complex than postulated by Greenberg and others (three peopling waves). Significant genetic input from outside is not noticed in Meso and South American Amerindians according to the phylogenetic analyses; while all world populations (including Africans, Europeans, Asians, Australians, Polynesians, North American Na-Dene Indians and Eskimos) are genetically related. Meso and South American Amerindians tend to remain isolated in the Neighbor-Joining, correspondence and plane genetic distance analyses.

The HLA profile of the Azoreans has been compared with those of other world populations in order to provide additional information regarding the history of their origins. The allele frequencies, genetic distances between populations, correspondence analyses and most frequent haplotypes were calculated. Our results indicate that the Azorean population most likely contains an admixture of high-frequency Caucasoid, Mongoloid and, to a lesser degree, Negroid HLA genes. The middle Atlantic Azores Archipelago was officially colonized by the Portuguese after 1439 and historical records are concordant with the existence of Caucasoid and Negroid population. However, Mongoloid genes were not suspected, but the Oriental HLA haplotypes A24-B44-DR6-DQ1, A29-B21-DR7-DQ2 and A2-B50-DR7-DQ2 are the fourth, fifth and sixth most frequent ones in Azores. A correspondence analysis shows that the Azorean population is equidistant from Asian and European populations and genetic distances are in some cases closer to the Asian than to European ethnic groups, and never are significantly different; also, B*2707 subtype is found in Asians and Azoreans (but not in Europeans) and the same Machado-Joseph Disease founder haplotypes (Chr 14) are found in both Japanese and Azoreans. It is proposed that a Mongoloid population exists in Azores; whether, the arrival occurred prior to discovery is undetermined.

HLA class I and class II expression was analyzed weekly by cytofluorometry on spermatozoa samples from four donors during a 15-wk trial. On the same day that semen samples were studied, and to analyze whether this expression was hormone-controlled, serum levels of testosterone, LH, FSH, inhibin B, activin, and pro-alphaC on the one hand, and seminal plasma levels of inhibin B, activin, and alpha-inhibin on the other, were also measured. Inhibin B and related peptides were quantitated using a novel two-site assay with monoclonal antibodies to the alpha and beta subunits of inhibin. Our results showed that HLA class I and class II molecules were expressed on the spermatozoa's surface, following a cyclic pattern, and that there was a simultaneous and coordinated expression of both types of molecules (r = 0.801, P < 0.0001). Furthermore, when the expression of these molecules was plotted against the different hormone levels, serum inhibin B showed a clear inverse correlation with HLA class I (r = -0.612, P < 0.0001) and class II (r = -0.534, P < 0.0001). This finding reveals unexpected functions of inhibin B, which may be relevant in the fertilization process and on male fertility control.