HLA class II allele frequencies in the Lebanese population

Aims

Being one of the most polymorphic genetic systems , the Human Leukocyte Antigen system is divided into class I (HLA-A, HLA-B and HLA-C) and class II (HLA-DP, -DQ and -DR). This study is the first and largest of its kind to describe the distribution of HLA-DQB1 and HLA-DRB1 alleles in Lebanon and the region.

Methods

Respectively, 560 and 563 Lebanese individuals referred for HLA typing and possible bone marrow/kidney donation were tested for HLA-DQB1 and HLA-DRB1 alleles using the polymerase chain reaction/sequence specific priming (PCR-SSP) method.

Results

Our data were compared to that of several populations with interesting common findings between the Lebanese, Jordanian, Bahraini, Saudi, Kuwaiti, Tunisian, Korean, Japanese, Thai, Irish, Bulgarian and Polish populations.

Conclusion

These data about the Lebanese population are going to aid future researchers to study the relation of HLA-DQB1 and HLA-DRB1 alleles with major and common diseases in the Lebanese population and will add to the available international literature associated with these loci. In addition it will serve as a reference for the future national bone marrow registry program in our country. We also reviewed the literature for the described association between HLA-DRB1 and -DQB1 loci and different disease entities.     

Effects of prenatal morphine on hypothalamic metabolism of neurotransmitters and gonadal and adrenal activities,during the early postnatal period in the rat

It is noteworthy that exposure to opiates during fetal development results in permanent changes in adults related to morphological, behavioral and biochemical measures; however little is known concerning the effects of such drugs in early postnatal life. We investigated in newborn rats the effects of prenatal morphine-exposure on both—the hypothalamic metabolism of norepinephrine (NE), serotonin (5 HT) and neuropeptide Y (NPY)—the activity of the hypothalamo-pituitary gonadal and adrenal axes. In a previous study performed in newborns of untreated mothers, we reported some sex-dependent changes in the metabolism of NE, 5 HT and NPY in the hypothalamus and an early activation of the gonadostimulating function and of the corticostimulating one. In control newborns from saline-treated mothers, a slight increase in the hypothalamic metabolism of NE (males) and 5 HT (males and females) was observed and it was comparable in both sexes. On the other hand, the hypothalamic content of NPY was unaffected in early postnatal period in newborn males as well as in females. These changes observed on hypothalamic metabolisms are temporally correlated with the early postnatal activation of the corticostimulating function in neonates of both sexes and that of the gonadostimulating one, mainly in males. Prenatal morphine exposure altered the hypothalamic metabolism of 5 HT which was increased mainly in newborn females but did not affect either the metabolism of NE or the NPY content of the hypothalamus. The more drastic effect of the prenatal morphine treatment is the atrophy and hypoactivity of the adrenals in newborns of both sexes at birth time and during the early postnatal period. In contrast morphine did not impair postnatal surge of the plasma testosterone level in male pups as well as late and slight increase of plasma estradiol in female ones.     

Identification of male-specific SNP markers and development of PCR-based genetic sex identification technique in crucifix crab (Charybdis feriatus) with implication of an XX/XY sex determination system

In this study, we first identified male-specific SNP markers using restriction site-associated DNA sequencing, and further developed a PCR-based sex identification technique for Charybdis feriatus. A total of 296.96 million clean reads were obtained, with 114.95 and 182.01 million from females and males. After assembly and alignment, 10 SNP markers were identified being heterozygous in males but homozygous in females. Five markers were further confirmed to be male-specific in a large number of individuals. Moreover, two male-specific sense primers and a common antisense primer were designed, using which, a PCR-based genetic sex identification method was successfully developed and used to identify the sex of 103 individuals, with a result of 49 females and 54 males. The presence of male-specific SNP markers suggests an XX/XY sex determination system for C. feriatus. These findings should be helpful for better understanding sex determination mechanism, and drafting artificial breeding program in crustaceans.     

Abundant androgen regulated mRNAs in mouse submandibular gland: cell-free translation of renin precursor mRNA

Submandibular glands of male mice contain at least four abundant mRNAs that occur at low concentrations in glands of females. The male-specific mRNAs code for polypeptides of 48,000, 43,000, 29,000, and 27,000 MW. Androgenic regulation of these mRNAs is illustrated by their apparent absence in glands of castrate males and by their accumulation in glands of females treated with testosterone. Selective hybrid-arrested translation experiments also indicate reduced levels of these male-specific sequences in female gland cytoplasm. The 48,000 MW male-specific polypeptide is reduced in translation products directed by gland mRNA from C57BL10/J mice (variants deficient in salivary renin), suggesting the corresponding mRNA codes for a renin precursor. The identity of this polypeptide is confirmed by immune selection with renin-specific antibody.     

Sex and strain differences of mouse variant salivary proteins

Proteins of the mouse saliva are resolved into about 20 discrete bands by polyacrylamide gel electrophoresis. Sexual dimorphism and monomorphism were found in a subset (Msp-1) of these salivary proteins from different inbred strains. This sexual dimorphism involves a fast moving band (F-type) and a slow moving one (S-type). Mature males of seven strains (A/J, AKR, CBA/J, C3H/HeN, A/Sn, B10.A, and B10.BR) exhibit the S phenotype while mature females of these strains were typed as F. Sexually immature males and females of these strains were uniformly typed as F, but at puberty (5-6 weeks of age) the phenotype of the males switched to type S, while the phenotype of the females remained the same. This switch to type S at puberty did not take place in males of four strains (BALB/cAnn, B10.D2, C57BL/6, and C57BL/10); therefore, we conclude that these strains were sexually monomorphic with regard to Msp-1. The phenotype of mature males of C3H/HeN reverted to type F following castration, whereas castrated males and mature females switched to type S in response to testosterone administration. The testosterone treatment had no effect on the type S phenotype of males and females of the sexually monomorphic BALB/cAnn strain. The male-specific type S phenotype of Msp-1 was seen only in mice with H-2 haplotype a or k; thus an association with H-2 haplotype was suggested. All F1 males of reciprocal crosses involving the sexually dimorphic and monomorphic strains (e.g., C3H/HeN X BALB/cAnn) demonstrated the type S phenotype at puberty.     

内蒙古地区蒙古族HLA-A、B、DRB1基因座多态性分析

应用序列特异性寡核苷酸探针反向斑点杂交技术对内蒙古地区蒙古族106名无关健康个体的HLA-A、B和DRB1 基因座进行基因分型, 以研究内蒙古地区蒙古族人群HLA-A、B、DRB1基因座的等位基因及其组成的单倍型频率分布特征。 采用最大数学预期值算法计算HLA基因座的等位基因频率和单倍型频率。106 名内蒙古地区蒙古族个体的HLA-A、B、DRB1基因座分别检出13、29、13个等位基因。高频单倍型分别为 HLA-A*02-B*46 (0.0510); HLA-A*02-B*13(0.0495); HLA-A*02-B*51(0.0442); HLA-B*13-DRB1*07 (0.0555); HLA- B*46-DRB1*09(0.0378); HLA-B*35-DRB1*13(0.03300); HLA-A*02-B*13-DRB1*07(0.033019); HLA-A*02-B*46- DRB1*09(0.031985)。研究表明: 内蒙古地区蒙古族人群HLA基因座的等位基因和单倍型具有较高的遗传多态性。HLA- A*24-B*14, HLA-A*32-B*63在该民族具有极强的连锁不平衡。     

Prenatal epidemiology of spontaneous cleft lip and palate, open eyelid, and embryonic death in A/J mice.

Nongenetic bases of variability in the frequencies of spontaneous cleft lip and palate (CLP), open eyelid (OL), and fetal resorption were searched for in A/J mouse litters of prenatal ages 17-21 days post-VP and parities 1-7. The malformation rates did not decrease with advancing fetal age, and hence prenatal elimination does not account for the lower rates seen in newborns. Multivariate analysis indicated that the frequencies of CLP and resorption were inversely related to maternal age and directly related to litter size, and that the frequency of OL was related, directly, only to litter size; but that none were associated with maternal weight, parity, and several other variables. Regarding uterine location, the frequency of CLP was higher at the ovarian and cervical sites, OL higher at the cervical site, and resorption lower at the ovarian site, than elesewhere. CLP was significantly commoner in females, and OL commoner in males; also, since the percentage of males increased with parity, the frequency of CLP in males relative to that in females decreased with parity, and that of OL increased. Malformed offspring weighed less than normal ones; and the sex with the lower frequency of CLP or OL had the greater weight reduction. The results are discussed in relation to the frequency of malformations in human fetuses and newborns.     

Colony-stimulating factor-1 blocks early pregnancy in mice

To elucidate the mechanisms underlying the suspected immune-related pregnancy failures in humans, we established experimental systems to induce pregnancy blocking and abortion in mice. One system, based on the preimmunization of C57BL/6J females with a syngeneic regressor tumor, is described. Such females fail to develop normal gestations when mated to C57BL/6J x DBA/2 F-1 (B6D2F-1) males or DBA/2 males but sustain normal pregnancies when impregnated by CBA/J or C57BL/6 males. An investigation into the cause of these male-specific pregnancy failures led us to identify colony-stimulating factor-1 (CSF-1) as responsible for both pregnancy-block and resorption of embryos. Indeed, injection of very small amounts of CSF-1 into plugged females, for the first 5 days of pregnancy, was sufficient to block B6D2F-1-induced gestations but had no effect on CBA/J-mated females. It also induced a high rate of fetal resorptions in the sensitive mating. These results suggest a novel mechanism underlying pregnancy failures: a mechanism based on cytokines and their effect on early embryonic development in certain mating combinations.     

Male-specific DNA sequences in pigs

One hundred primers (Operon kits OPAA, OPAO, OPAV, OPC, and OPE series) were used for random amplified polymorphic DNA (RAPD) fingerprinting to determine male-specific fragments. Seventy-four percent of the primers yielded Yorkshire polymorphic fragments. One of these primers, OPAV-18, produced a novel 1098-bp DNA fragment found only in tested males. This male-specific fragment was isolated and constructed into plasmids for nucleotide sequencing. Two primers (5'-TTGCTCACGG TAGATAACAA GAGAG-3' and 5'-TTGCTCACGG ACCAGGTAGG GAATG-3') were designed according to the cloned male-specific sequence to amplify the male-specific band using polymerase chain reaction (PCR) for pig sexing. Sex-specific bands in the PCR gel products were represented in males but none were found in females when Yorkshire, Duroc, and Landrace genomic DNA samples were amplified with these two primers by PCR. The PCR products in the gel were transferred to nylon membranes and hybridized with a 32P-dCTP labeled probe of the cloned male-specific DNA fragment. There was a clear hybridization signal in samples from all of the male pigs, but not from those of female pigs. Male and female genomic DNA samples from these pigs were spotted onto nylon membranes and hybridized with the male-specific probe. The probe hybridized strongly to males only. A high degree of sequence homology was found among the novel male-specific DNA sequences in Yorkshire, Duroc and Landrace. The sex of these three breeds of pigs could be easily and effectively determined using these two primers.     

Differentiation of a Male-Specific Muscle in Drosophila Melanogaster Does Not Require the Sex-Determining Genes Doublesex or Intersex

A pair of muscles span the fifth abdominal segment of male but not female Drosophila melanogaster adults. To establish whether genes involved in the development of other sexually dimorphic tissues controlled the differentiation of sex-specific muscles, flies mutant for five known sex-determining genes were examined for the occurrence of male-specific abdominal muscles. Female flies mutant for alleles of Sex-lethal, defective in sex determination, or null alleles of transformer or transformer-2 are converted into phenotypic males that formed male-specific abdominal muscles. Both male and female flies, when mutant for null alleles of doublesex, develop as nearly identical intersexes in other somatic characteristics. Male doublesex flies produced the male-specific muscles, whereas female doublesex flies lacked them. Female flies, even when they inappropriately expressed the male-specific form of doublesex mRNA, failed to produce the male-specific muscles. Therefore, the wild-type products of the genes Sex-lethal, transformer and transformer-2 act to prevent the differentiation of male-specific muscles in female flies. However, there is no role for the genes doublesex or intersex in either the generation of the male-specific muscles in males or their suppression in females.     

Sex and strain differences of mouse variant salivary proteins

Abstract. Proteins of the mouse saliva are resolved into about 20 discrete bands by polyacrylamide gel electrophoresis. Sexual dimorphism and monomorphism were found in a subset (Msp-1) of these salivary proteins from different inbred strains. This sexual dimorphism involves a fast moving band (F-type) and a slow moving one (S-type). Mature males of seven strains (A/J, AKR, CBA/J, C3H/HeN, A/Sn, B10.A, and B10.BR) exhibit the S phenotype while mature females of these strains were typed as F. Sexually immature males and females of these strains were uniformly typed as F, but at puberty (5–6 weeks of age) the phenotype of the males switched to types, while the phenotype of the females remained the same. This switch to type S at puberty did not take place in males of four strains (BALB/cAnn, B10.D2, C57BL/6, and C57BL/10); therefore, we conclude that these strains were sexually monomorphic with regard to Msp-1. The phenotype of mature males of C3H/HeN reverted to type F following castration, whereas castrated males and mature females switched to type S in response to testosterone administration. The testosterone treatment had no effect on the type S phenotype of males and females of the sexually monomorphic BALB/cAnn strain. The male-specific type S phenotype of Msp-1 was seen only in mice with H-2 haplotype a or k; thus an association with H-2 haplotype was suggested. All F₁ males of reciprocal crosses involving the sexually dimorphic and monomorphic strains (e.g., C3H/HeN × BALB/cAnn) demonstrated the type S phenotype at puberty.     

Reproductive success by large, closely related males facilitated by sperm storage in an aggregate breeding amphibian

The outcome of sexual selection on males may depend on female mate choice and male–male competition as well as postcopulatory processes such as cryptic female choice and sperm competition. We studied the outcome of sexual selection in the spotted salamander ( Ambystoma maculatum ), specifically examining the role of body size and relatedness on male reproductive success. Using controlled mating experiments in the field, we gave females access to three males of different sizes. We used seven microsatellite loci to determine paternity in the resulting larvae, estimate relatedness ( r ) between females and their mates, and calculate md ² (a measure of within-individual genomic divergence), heterozygosity, and standardized heterozygosity in the larvae. Both body size and relatedness to the female were significant predictors of male reproductive success. The relatedness of the males available to a female did not influence the amount of stored sperm she used to sire her larvae. Nonetheless, computer simulations showed that the average md ², heterozygosity, and standardized heterozygosity of the offspring were lower than expected by random mating. These differences are due to the use of stored sperm to fertilize some eggs; md ², heterozygosity, and standardized heterozygosity of larvae sired by stored sperm were significantly lower than those of larvae sired by the experimental males. These results suggest that relatedness may further influence a male's long-term reproductive success by determining whether his sperm is stored for later breeding seasons. Sexual selection in this salamander likely involves a complex interaction among many factors and may act over many seasons.     

The clinical immunogenetics of viral hepatitis C in a Caucasoid population of western Siberia

The analysis of the immunogenetic studies on hepatitis C patients among the Caucasoid population of western Siberia has revealed a significant increase in the detection rate of antigens HLA-A10 and HLA-DR5, the combinations of DR2-DR5, DR5-DR7, DR1-B27 and the complete absence of antigen HLA-DR4, which is indicative of the fact that susceptibility and resistance to the development of the disease is associated with the genes of the main histocompatibility complex. In hepatitis of mixed etiology, B and C, a significant increase in the occurrence of HLA antigens: -A1, -B8, -DR1 and -DR3, as well as the combinations of A1-DR1, A1-DR3, A3-DR3, A9-A10, DR1-DR3, B8-DR3 is noted; at the same time a decrease in the occurrence of antigen DR4 and its combination with antigen HLA-A2 is observed.     

Microsatellite-directed selection of breeders for the next backcross generation by using a minimal number of loci

To establish a minimal number of markers for direct selection of candidate mice used for the next mating to produce congenic mice, recombination frequencies of 53 microsatellite loci on chromosomes (chr.) 1 and 19 were examined using 41 N2 mice: the donor strain was BALB/c, and recipient strain was C57BL/6J (B6J) or C57BL/6N (B6N). These markers were spaced at 0.1 to 24.2 centimorgans (cM). Among the 41 mice, B6/B6 homozygosity ranged from 18 to 24 animals (mean, 20; 2 standard deviations, 1.36) for a given locus. There was no difference in recombination frequency between chr. 1 and 19. The recombination frequency of B6J was higher than that of B6N (P < 0.05). Various densities of markers, 10 (5 markers/chr.), 8 (4 markers/chr.), and 6 (3 markers/chr.) spaced at 12.0 to 29.3, 9.0 to 45.0, and 24.5 to 53.0 cM, respectively, were selected from the 53 markers, and homozygosity was compared in each mouse. In mice with decreased homozygosity when tested using 53 markers, homozygosity differed depending on the density of the markers. The results suggested that 3 markers/chr. are sufficient for selection of the highest percentages of homozygosity but are not suitable to define mice with lower percentages of homozygosity.     

Uncoupling the roles of HLA-DRB1 and HLA-DRB5 genes in multiple sclerosis

Genetic susceptibility to multiple sclerosis (MS) is associated with the MHC located on chromosome 6p21. This signal maps primarily to a 1-Mb region encompassing the HLA class II loci, and it segregates often with the HLA-DQB1*0602, -DQA1*0102, -DRB1*1501, -DRB5*0101 haplotype. However, the identification of the true predisposing gene or genes within the susceptibility haplotype has been handicapped by the strong linkage disequilibrium across the locus. African Americans have greater MHC haplotypic diversity and distinct patterns of linkage disequilibrium, which make this population particularly informative for fine mapping efforts. The purpose of this study was to establish the telomeric boundary of the HLA class II region affecting susceptibility to MS by assessing genetic association with the neighboring HLA-DRB5 gene as well as seven telomeric single nucleotide polymorphisms in a large, well-characterized African American dataset. Rare DRB5*null individuals were previously described in African populations. Although significant associations with both HLA-DRB1 and HLA-DRB5 loci were present, HLA-DRB1*1503 was associated with MS in the absence of HLA-DRB5, providing evidence for HLA-DRB1 as the primary susceptibility gene. Interestingly, the HLA-DRB5*null subjects appear to be at increased risk for developing secondary progressive MS. Thus, HLA-DRB5 attenuates MS severity, a finding consistent with HLA-DRB5's proposed role as a modifier in experimental autoimmune encephalomyelitis. Additionally, conditional haplotype analysis revealed a susceptibility signal at the class III AGER locus independent of DRB1. The data underscore the power of the African American MS dataset to identify disease genes by association in a region of high linkage disequilibrium.     

HLA genes and haplotypes in Ryukyuans suggest recent gene flow to the Okinawa Islands.

Polymorphism of HLA genes was investigated in a population sample of Ryukyuans living on the main island of Okinawa (n = 197), in the southwestern islands of Japan. Serological typing was applied to class I loci (HLA-A, -B, and -C) and to HLA-DRB1; nucleotide sequence-level typing was performed using PCR microtiter plate hybridization and PCR single-strand conformation polymorphism methods. Ryukyuans showed a higher frequency of DRB1*0405 and lower frequencies of DRB1*1502 and DRB1*1302 compared with Hondo Japanese living on main islands. Principal components and phylogenetic analyses of 12 East Asian populations, including Ryukyuans, were performed based on the allele frequencies of HLA-A, -B, and -DRB1. In the principal components analysis 3 Japanese populations (Ryukyuans, Hondo Japanese, and Ainu) formed a cluster and showed the highest affinity to 2 Korean populations. In the phylogenetic tree Ryukyuans and Ainu were neighbors, but the genetic distance between them was larger than the distances between Ryukyuans and Hondo Japanese and between Ryukyuans and Korean populations. The geographic cline of the predominant haplotype in Ryukyuans, A*24-B*54-DRB1*0405, suggests that an ancestral population possessing A*24-B*54-DRB1*0405 moved into the Okinawa Islands after the divergence of Ryukyuans from the Ainu. Such a recent gene flow, probably from South China to the Okinawa Islands, is considered the major cause of difference in genetic characteristics between Ryukyuans and the Ainu.     

The influence of birth order on birth weight: does the sex of preceding siblings matter?

The purpose of this study was to investigate whether the well-established relationship between parity and birth weight is affected by the sex composition of siblings, especially for male newborns. Subjects were 856 male and 862 female newborns who weighed at least 2500 g at birth, who were born after 37 completed weeks of gestation, who obtained an Apgar score of 7 or higher, who had the same biological parents as all other children in the sibship, and who lived in the same household. Information on birth weight was collected from hospital records. Results showed that male newborns with older brothers weighed less than male newborns with older sisters. In contrast, the weight of female newborns with older brothers did not differ from the weight of female newborns with older sisters. One explanation of these results is that maternal immunoreactivity to some male-specific feature of the fetus affects prenatal development and consequently reduces birth weight in males. The relation between older brothers and birth weight may have theoretical significance for behavioural variables.     

Recombination in the X chromosome of Drosophila melanogaster females heterozygous for two autosomal translocations

X chromosome recombination was measured in females carrying two 2; 3-translocations. Total X chromosome recombination values varied according to the amount of structural heterozygosity between the two translocations. The results support the hypothesis that the observed effects of autosomal translocation homozygosity on recombination in the X chromosome are due to homozygosity for position effects of the translocation breakpoints and are not due to chromosome discontinuity.     

Stay or stray? Evidence for alternative mating strategy phenotypes in both men and women

In all comparative analyses, humans always fall on the borderline between obligate monogamy and polygamy. Here, we use behavioural indices (sociosexuality) and anatomical indices (prenatal testosterone exposure indexed by 2D : 4D digit ratio) from three human populations to show that this may be because there are two distinct phenotypes in both sexes. While males are more promiscuous and display higher prenatal testosterone exposure than females overall, our analyses also suggest that the within-sex variation of these variables is best described by two underlying mixture models, suggesting the presence of two phenotypes with a monogamous/promiscuous ratio that slightly favours monogamy in females and promiscuity in males. The presence of two phenotypes implies that mating strategy might be under complex frequency-dependent selection.