Polymorphism at the beta-adrenergic receptor (ADRB3) locus of Merino sheep and its association with lamb mortality

Beta3-adrenergic receptors are predominantly found on the surface of adipocytes and are major mediators of the lipolytic and thermogenic effects of high catecholamine concentrations. Recently, variation in the ovine beta3-adrenergic receptor (ADRB3) gene has been reported to be associated with lamb survival. In this study, polymerase chain reaction-single strand conformational polymorphism analysis of part of the ADRB3 intron was used to genotype 4488 Merino lambs born at 10 farms throughout the South Island of New Zealand. Univariate and multivariate odds ratios for each allele revealed a significant association of the E allele with cdd survival and of the D allele with mortality. This variation at the ADRB3 locus may assist in the genetic selection for survival in Merino sheep.     

Genetic polymorphism in sheep plasma detected using antibodies to human plasminogen

Protein variation was identified in sheep when Western blots of polyacrylamide gels (routinely used to resolve transferrin polymorphism) were stained using antibodies to human plasminogen. The affinity of the antibodies to ovine plasma was less than 7% that of a human standard but they bound specifically to a single polymorphic protein. In 146 lambs and their parents the inheritance of the ovine plasminogen antigen polymorphism was consistent with four autosomal alleles segregating codominantly. However, an additional two lambs had types which were incompatible with their putative parents. The pedigrees of these lambs were tested by DNA fingerprinting and shown to have been incorrectly recorded. The genetic polymorphism detected by human plasminogen antiserum provided a probability of sire exclusion (PE) ranging from 0.04 to 0.32 and a polymorphic information content (PIC) of 0.08 to 0.50 in flocks of five sheep breeds: Perendale, Romney, Merino, Texel and Coopworth (in order of increasing genetic variation in this locus). Significant differences in allele frequency were observed between breeds but sampling did not assess the variation among flocks within a breed.     

Polymorphism of the ovine β3-adrenergic receptor gene (ADRB3) and its association with wool mean staple strength and yield

We investigated the possibility that variation in ovine ADRB3 is associated with various wool traits, in particular mean staple strength (MSS). Polymerase chain reaction-single strand conformational polymorphism analysis of part of the ADRB3 intron was used to genotype 695 Merino lambs born on three farms in the South Island of New Zealand and which were shorn as 2-tooths. For each fleece, MSS, mean fibre diameter, mean staple length and yield were measured. The results from mixed-effects models and half-sib analyses suggest that ADRB3 alleles A and D have a negative impact on some wool traits, whereas ADRB3 alleles C and E appear to have a positive impact, with allele C potentially having a greater impact than allele E on MSS. This variation in the ADRB3 may assist in the genetic selection for increased MSS and yield in Merino sheep.     

Extensive Diversity of the ADRB3 Gene in Chinese Sheep Identified by PCR-SSCP

The β₃-adrenergic receptor (ADRB3) is the main mediator of the lipolytic and thermogenic effects of high catecholamine concentrations. Polymorphism in the ovine ADRB3 gene has been reported to be associated with birth weight, growth rate, carcass composition, and cold survival. Eight alleles have been identified in New Zealand sheep, but to date, breeds from other countries have not been studied in detail. In this study, we employed PCR-SSCP to detect ADRB3 polymorphism in the Hu, Tan, small-tailed Han, and Tibet breeds of Chinese sheep. Thirteen SSCP patterns were observed, including the eight previously reported and five new patterns. The newly identified SSCP patterns represent five novel sequences, increasing the reported number of alleles of ADRB3 from 8 to 13. In these Chinese sheep, the most common allele was the previously reported allele C (49.0%); the A allele was the next most common (22.0%). These results suggest that Chinese sheep have more diversity in ADRB3 than New Zealand sheep and therefore have possibly been selected either naturally or via breeding for different traits.     

Polymorphism of the bovine ADRB3 gene

The β₃-adrenergic receptor (ADRB3) is predominantly expressed in white and brown adipose tissue and mediates the lipolytic and thermogenic effects of high catecholamine concentrations. Variation in the ADRB3 gene (ADRB3) has been associated with obesity and the earlier onset of non-insulin-dependent diabetes mellitus in some ethnic groups, as well as some production traits of sheep, but to date variation of bovine ADRB3 has not been reported. In this study, variation in the promoter region of bovine ADRB3 was investigated in 737 cattle by polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) analysis. Six PCR-SSCP patterns representing six allelic variations and containing four single nucleotide polymorphisms (SNPs) and three nucleotide deletions/insertions were observed. Allele A was the most common allele (93.83%), whereas alleles C, D, E and F were rare (0.07, 1.09, 0.41, and 0.34%, respectively). The variation identified here might have an impact on both the function and level of expression of bovine ADRB3.     

中国成都地区汉族人群DHFRP2位点的遗传多态性研究

用扩增片断长度多态性技术分析短串联重复序列（STR）DHFRP2位点的DNA多态性, 在156个中国成都地区汉族无关个体中发现6个等位基因,19种基因型,并首次发现一重复单元数不是4的整数倍的等位基因,该等位基因按孟德尔遗传规律遗传。观察的基因型分布符合Hardy-Weinberg定律,其个人鉴别力（DP）为0.87,杂合度为67.3%,多态性信息量（PIC）为0.68,非父排除率（CE）为45.5%,家系分析结果表明, 该位点符合孟德尔遗传法则。 Abstract：　Analyzes polymorphism of short tandem repeat locus (DHFRP2) by using Amp-FLP. Six alleles and nineteen genotypes were observed in 156 unrelated individuals of Chinese Hans in Chengdu. Meanwhile, we first discovered a new allele, its repeat monomers is not integral times of four, which is in conformity with Mendelian inheritance. The allelic discriminating power (DP), observed heterozygocity (h), polymorphism information content (PIC) and chances of paternity exclusion (CE) are 0.87, 67.3%, 0.68 and 45.5% respectively. The distribution of its genotypes tally with Hardy-Weinberg equilibrium and family study manifested that the locus is in conformity with medelian inheritance.     

The genetics of the sixth and seventh components of complement in the dog: Polymorphism,linkage, locus duplication,and silent alleles

The complement components C6 and C7 exhibit genetic polymorphism in the domestic dog. In the case of C6, there is a single locus with a null allele and two structural alleles; in the case of C7, there are two linked loci, each with three structural alleles. There is a null allele or locus deletion at one of these loci. In all cases, inheritance is autosomal and codominant. The C7 loci are closely linked to each other and to C6. This complex is not close to the dog major histocompatibility complex (MHC) locus.     

凡纳滨对虾微卫星位点在两个选育家系中遗传的初步研究

利用两个选育凡纳滨对虾全同胞家系研究了10个微卫星位点的遗传特征。通过ABI310或3100测序仪检测, 在所观察到的20个基因型比例（genotypic ratios）(10个微卫星位点 X 2个家系)中,有17个基因型比例符合孟德尔遗传。微卫星位点TUMXLv8.220在两个家系中均存在无效等位基因,从而3个不符合孟德尔遗传基因型中2个可由无效等位基因来解释。TUMXLv 3.1在06家系偏离了1：1：1：1的孟德尔预期比。3个微卫星位点（TUMXLv5.66,TUMXLv7.74,TUMXLv8.224）在两个家系中均表现单态。3个微卫星位点（TUMXLv5.45,TUMXLv7.56,TUMXLv8.256）在两个家系均既表现多态又遵循孟德尔共显性遗传, 是亲子鉴定和种群遗传分析的较好选择。结果显示在应用微卫星标记进行遗传分析之前利用全同胞家系进行遗传模式研究是非常必要的。     

Variation at Two Loci affecting Homoeologous Meiotic Chromosome Pairing in <Emphasis Type="Italic">Triticum aestivum</Emphasis> × <Emphasis Type="Italic">Aegilops mutica</Emphasis> Hybrids

HOMOEOLOGOUS chromosomes of the three genomes of bread wheat (Triticum aestivum 2n=6x=42) are normally prevented from pairing at meiosis by the activity of an allele at the Ph locus on chromosome 5B^L (refs. 1–4). This activity is responsible for the regular bivalent-forming meiotic behaviour and for the stable disomic inheritance of T. aestivum. If allelic variation occurs at the PA locus in nature it is extremely rare, although mutation has been induced and mutant alleles isolated^3,4.     

Human-Specific SNP in Obesity Genes, Adrenergic Receptor Beta2 (ADRB2), Beta3 (ADRB3), and PPAR γ2 (PPARG), during Primate Evolution

Adrenergic-receptor beta2 (ADRB2) and beta3 (ADRB3) are obesity genes that play a key role in the regulation of energy balance by increasing lipolysis and thermogenesis. The Glu27 allele in ADRB2 and the Arg64 allele in ADRB3 are associated with abdominal obesity and early onset of non-insulin-dependent diabetes mellitus (NIDDM) in many ethnic groups. Peroxisome proliferator-activated receptor γ (PPARG) is required for adipocyte differentiation. Pro12Ala mutation decreases PPARG activity and resistance to NIDDM. In humans, energy-expense alleles, Gln27 in ADRB2 and Trp64 in ADRB3, are at higher frequencies than Glu27 and Arg64, respectively, but Ala12 in PPARG is at lower frequency than Pro12. Adaptation of humans for lipolysis, thermogenesis, and reduction of fat accumulation could be considered by examining which alleles in these genes are dominant in non-human primates (NHP). All NHP (P. troglodytes, G. gorilla, P. pygmaeus, H. agilis and macaques) had energy-thrifty alleles, Gly16 and Glu27 in ADRB2, and Arg64 in ADRB3, but did not have energy-expense alleles, Arg16, Gln27 and Trp64 alleles. In PPARG gene, all NHP had large adipocyte accumulating type, the Pro12 allele. CONCLUSIONS: These results indicate that a tendency to produce much more heat through the energy-expense alleles developed only in humans, who left tropical rainforests for savanna and developed new features in their heat-regulation systems, such as reduction of body hair and increased evaporation of water, and might have helped the protection of entrails from cold at night, especially in glacial periods.     

Mutation rate in the hypervariable VNTR g3 (D7S22) is affected by allele length and a flanking DNA sequence polymorphism near the repeat array.

The hypervariable human minisatellite locus D7S22 (g3) is highly polymorphic. The allelic distribution in D7S22 features a size clustering of the alleles and a comparably low allelic diversity among small alleles. This reduced diversity could reflect a situation where some alleles are less likely to mutate than others. Several factors could explain such an effect, including allele size, variation in repeat composition, and allelic differences in nearby cis-acting elements affecting the mutation rate. We have characterized 40 de novo mutations found on Southern blots in a large amount of paternity-testing material. There is a significant excess of paternal mutations, and small size changes are most frequent. Mutation rate is affected by allele length, with highest rates in larger alleles. Alleles of the family groups with D7S22 mutations and 50 small alleles were analyzed by nucleotide sequencing. Two hundred thirty-six base pairs of the immediate flanking region upstream of the repeat array were PCR amplified and screened for point mutations by DNA sequencing of the PCR products. Two base substitution polymorphisms were identified: one C/G transversion and one A/G transition, 54 bp and 173 bp upstream of the repeat array, respectively. There is a significant association between mutation and occurrence of 54C, while association is not obvious between mutation rate and the 173A/G variants. There is a marked association between different flanking haplotypes and allele size, and within the smallest allele-size group, all alleles had the 54G/173A haplotype. Both allele size and allelic state at site 54 remain associated with mutation rate when the other factor is controlled. Possible mechanisms behind the variation in mutation rate in D7S22 are discussed.     

基于荧光定量PCR扩增反应的SNP测定法

建立一种利用荧光定量PCR扩增反应进行单核苷酸多态性(SNP)快速测定的方法.以人β肾上腺素受体2基因中的Arg16Gly为研究对象,利用荧光染料SYBRGreenⅠ标记定量PCR产物,通过PCR生长曲线和融解曲线分析结果进行SNP分型.为提高SNP测定的特异性,分别在野生型和突变型等位基因的特异性引物3′端倒数第3个碱基位置,引入了一个人为错配碱基,使引物的错误延伸率显著降低,大大提高了SNP分析的准确性.通过DNA测序验证荧光定量PCR对β肾上腺素受体2基因中Arg16Gly分型结果的准确率.实验结果表明,所建立的方法操作简便,结果准确,适合进行大规模样品的SNP检测工作.     

Evidence for co‐dominant allelic expression of a phosphoglucomutase regulatory locus polymorphism in the Atlantic salmon

Starch gel electrophoresis of the phosphoglucomutase isozyme, PGM‐1, in liver tissue in Atlantic salmon Salmo salar shows three phenotypes – full, partial and no expression. The genetic basis of the variation has not been established. Studies of the inheritance of the variation and of liver enzyme levels carried out indicate that the variation, as in rainbow trout Onchorynchus mykiss , reflects co‐dominant allelic variation at a cis ‐acting regulatory locus, designated PGM‐1r *, with one allele promoting and the other suppressing expression.     

Study of five haemogenetic markers (Gc, C3, Bf, Ag, and GALT) in six Indonesian populations and in 12 subgroups of Balinese

In various ethnic groups of the Indonesian archipelago and of Bali, the polymorphisms of the serum proteins Gc globulin (vitamin D-binding protein), C3 (complement component 3), Bf (complement factor B), Ag x,y (lipoprotein allotypes), and of the red cell enzyme system GALT (galactose-1P-uridyltransferase) were analysed. Among the studied proteins, the Gc system was the most informative one for the anthropologist. Besides considerable differences of frequencies of the common alleles Gc*1F, Gc*1S and Gc*2, a number of rare alleles (1A1, 1A3, 1A8, 1A9, 1A12, 1C2, 1C21, 1C24, and 2C8) and some new ones (1C28, 1C29, 1C30, 2C9) were observed. The presence of Gc*1A1 demonstrates the relationship to the Australo-Melanesian populations, but Mongolian variants (1A3, 1A8, 1A9, 1C2) were also encountered. Within the C3 system a very high frequency of the C3*S allele was observed in all populations. The rare alleles C3*F0.55, C3S1, and C3*S0.5 were observed in some groups. A new allele (C3*F0.35) was detected in a Chinese individual and in a nobleman from Bali. The frequency of the Bf*F allele was rather low in general, and the Bf*S0.7 allele was found in three Indonesian individuals only. The Ag*(x) frequencies were rather high, as it is known for Asiatic populations. Variability among subgroups was not very pronounced. The GALT*2 allele (Duarte variant of the enzyme) was observed very rarely; however, it was present in several populations. Enzyme activities could not be determined, and therefore we cannot tell whether the galactosaemia gene (GALT*0) was present or not.     

The evolution of sex-independent transmission ratio distortion involving multiple allelic interactions at a single locus in rice

Transmission ratio distortion (TRD) is frequently observed in inter- and intraspecific hybrids of plants, leading to a violation of Mendelian inheritance. Sex-independent TRD (siTRD) was detected in a hybrid between Asian cultivated rice and its wild ancestor. Here we examined how siTRD caused by an allelic interaction at a specific locus arose in Asian rice species. The siTRD is controlled by the S(6) locus via a mechanism in which the S(6) allele acts as a gamete eliminator, and both the male and female gametes possessing the opposite allele (S(6)(a)) are aborted only in heterozygotes (S(6)/S(6)(a)). Fine mapping revealed that the S(6) locus is located near the centromere of chromosome 6. Testcross experiments using near-isogenic lines (NILs) carrying either the S(6) or S(6)(a) alleles revealed that Asian rice strains frequently harbor an additional allele (S(6)(n)) the presence of which, in heterozygotic states (S(6)/S(6)(n) and S(6)(a)/S(6)(n)), does not result in siTRD. A prominent reduction in the nucleotide diversity of S(6) or S(6)(a) carriers relative to that of S(6)(n) carriers was detected in the chromosomal region. These results suggest that the two incompatible alleles (S(6) and S(6)(a)) arose independently from S(6)(n) and established genetically discontinuous relationships between limited constituents of the Asian rice population.     

Milk production and composition,and progeny performance in young ewes with high merit for rapid growth and muscle and fat accumulation

In ewe lambs, acceleration of growth and accumulation of both muscle and fat leads to earlier sexual maturity and better reproductive performance. The next stage in the development of this theme is to test whether these aspects of growth in young ewes affect milk production in their first lactation and the growth of their first progeny. We studied 75 young Merino ewes that had known phenotypic values for depth of eye muscle (EMD) and fat (FAT), and known Australian Sheep Breeding Values for post-weaning weight (PWT) and depths of eye muscle (PEMD) and fat (PFAT). They lambed for the first time at 1 year of age. Their lambs were weighed weekly from birth to weaning at 10 weeks to determine live weight gain and weaning weight. Progeny birth weight was positively associated with live weight gain and weaning weight (P<0.001). The PWT of the mothers was positively associated with birth weight (P<0.01), live weight gain and weaning weight of the progeny (P<0.05); however, these progeny traits were not influenced by EMD, FAT, PEMD, PFAT of the mothers (P>0.05). The PWT of the sire was positively associated with live weight gain (P<0.05) and weaning weight of the progeny (P<0.01). At around day 20 postpartum, we measured milk production and milk composition (fat, protein, lactose, total solids). Milk production was influenced positively by birth type (single or twin; P<0.05) and negatively by birth weight (P<0.05), but not by mother phenotype or genotype, sire genotype of the mother or the sex of the progeny (P>0.05). The concentrations of fat, protein, lactose and total solids in the milk were not affected by the phenotype or genotype of the mothers or of the sires of the mothers, or by the sex of the progeny (P>0.05). We conclude that selection of young Merino ewes for better growth, and more rapid accumulation of muscle and fat, will lead to progeny that are heavier at birth, grow faster and are heavier at weaning. Moreover, milk production and composition do not seem to be affected by the genetic merit of the mother for post-weaning live weight or PEMD or PFAT. Therefore, Merino ewes can lamb at 1 year of age without affecting the production objectives of the Merino sheep industry.     

Identification of fecundity gene (FecB) carriers using microsatellite markers and its effect on sheep weight

Abstract. Altogether 115 animals representing 5 genetic groups: 3 purebred Booroola Merino, Corriedale and Olkuska, and 2 Booroola crossbreds were included in the studies. In total 6 alleles from 97 bp to 119 bp in microsatellite OarAE101, and 5 alleles from 162 bp to 174 bp in BM1329 were identified. The marker of FecB gene presence seems to be an allele of 97 bp in the case of microsatellite OarAE 101 and 162 bp in the case of BM1329. Significant differences FecB carriers (Booroola-Corriedale) and non-carriers (Corriedale) in birth weight and at weaning at 100 days (males and females from twins) as well as weight gain during the first 28 days and 100 days were found. Purebred lambs showed higher values of the investigated traits.     

Distinctions among Allelic Variants Associated with Chromosome 3 Inversions in DROSOPHILA PSEUDOOBSCURA and DROSOPHILA PERSIMILIS

Efforts were made to discriminate new genetic variants among electrophoretic alleles that are associated with chromosome 3 inversions of Drosophila pseudoobscura and D. persimilis. Apparent genetic similarities for electrophoretic alleles between these two species and among the common inversions they carry were reexamined by altering gel concentration and buffer pH. At the amylase locus, the 1.09 electrophoretic allele could be further separated into two allelic classes that differentiated the WT and KL arrangements. Similarly, the 0.84 electrophoretic allele was divided into two allelic classes, one characteristic of the Santa Cruz phylad arrangements, TL and SC, and the other found in strains of the Standard phylad arrangements and CH. Uncommon amylase alleles proved to be different alleles in the two species. No new allelic variants, however, could be found among strains with the amylase 1.00 allele, the commonest allele in the Standard phylad of both species. No major new allelic variation was detected for acid phosphatase-3 and larval protein-10 that revealed any further differentiation among species or inversions. Variation at all three loci in strains of the Bogota population remained genetically similar to variation in strains of mainland D. pseudoobscura.     

Plasma paraoxonase polymorphism: a new enzyme assay, population, family, biochemical, and linkage studies.

Plasma paraoxonase hydrolyzes paraoxon, the principal metabolite of the insecticide parathione. A genetic polymorphism for enzyme activity has been previously demonstrated. We describe a new assay based on the differential inhibition by EDTA of plasma paraoxonase from persons with the high-activity allele (PX*H) that suggests a trimodality of activity levels in population studies. The gene frequency of the low activity allele (PX*L) in 531 Seattle blood donors of European origin was .7207. Family studies were consistent with codominant autosomal inheritance of two alleles, PX*L (low) and PX*H (high), coding for products with different activity levels. Biochemical measurements of sera from presumed homozygotes for the two different alleles revealed minor physicochemical differences suggestive of a structural difference between the allelic products. No evidence for linkage of the paraoxonase locus with any of 19 polymorphic markers would be detected.     

Heritability of the maternal meiotic drive system linked to Om and high-resolution mapping of the Responder locus in mouse

Matings between (C57BL/6 x DDK)F(1) females and C57BL/6 males result in a significant excess of offspring inheriting maternal DDK alleles in the central region of mouse chromosome 11 due to meiotic drive at the second meiotic division. We have shown previously that the locus subject to selection is in the vicinity of D11Mit66, a marker closely linked to the Om locus that controls the preimplantation embryo-lethal phenotype known as the "DDK syndrome." We have also shown that observation of meiotic drive in this system depends upon the genotype of the sire. Here we show that females that are heterozygous at Om retain the meiotic drive phenotype and define a 0.32-cM candidate interval for the Responder locus in this drive system. In addition, analysis of the inheritance of alleles at Om among the offspring of F(1) intercrosses indicates that the effect of the sire is determined by the sperm genotype at Om or a locus linked to Om.