Blood groups and biochemical polymorphism in the Namaqua sheep breed

Summary. The Namaqua is an indigenous fat-tailed African breed of sheep which has remained relatively isolated and which at one time dwindled to near extinction. Frequency data are given for blood group antigens, red cell glutathione and potassium types, for electrophoretic variants of red cell haemoglobin, 'X' protein, nucleoside phosphorylase, NADH-diaphorase, lysine and carbonic anhydrase and of plasma esterase, transferrin and albumin. Of particular interest was the occurrence of the i blood group, a bimodal distribution in red cell glutathione concentrations and red cell potassium concentrations of around 57 mmo1/1 cells, i.e. neither typically LK nor HK type.     

Haemoglobin and transferrin polymorphism in the Muzaffarnagri breed ofsheep and its crosses with Corriedale

Allelic frequencies for haemoglobins and transferrins in the Muzaffarnagri breed of sheep have been reported. All the three haemoglobin types were recorded. Seven transferrin phenotypes, TfAB, TfAD, TfBB, TfBC, TfBD, TfBE and TfDD, were observed. The gene frequencies for TfA, TfB, TfC, TfD and TfE were 0.032, 0.330, 0.001, 0.620 and 0.010, respectively.     

Haemoglobin variants in cattle

From a comparative survey of reports on cattle Hb variants it is concluded that prior to the present communication the occurrence of at least seven different adult Hb molecules have been reported.
In addition comes the finding of a new Hb variant called HbG which is reported in this study. This was found in three animals among 101 East African Zebu cattle. It migrated more slowly than any cattle Hb variant previously reported and made up 20% of total Hb.
The gene frequencies of the East African Zebu population were: Hb^A = 0.52, Hb^B = 0.32, Hb^c = 0.14 and Hb^G = 0.01.     

Cytogenetic and genetic study of a Y-linked microsatellite polymorphism in Polish Black-and-White cattle breed

The aim of the current study was to characterize Polish Black-and-White cattle by morphological study of the Y chromosome. A total of 14 Y-linked microsatellites from UMN and INRA group were genotyped and assessed for polymorphism in a total 22 bulls. Cytogenetic studies in Polish Black-and-White bulls showed the existence of two morphological forms of Y chromosome. Among the 22 karyotypic analyzed bulls, 12 had submetacentric and 10 metacentric Y chromosome. The centromeric index of Y chromosome measured as percentage length of the p arm to total length ratio in the first case was 28 ± 3.97% and in the second 47 ± 7.28%, whereas the relative size of these chromosomes remained within the same range. Morphology and G- and C-banding patterns of both forms of Y chromosome were typical for other cattle breeds originating from Bos taurus. Out of a total of 14 microsatellite loci examined, 13 showed specific alleles for two forms of Y chromosome. In a pool of 62 alleles, 43 (69.3%) were common in the two groups of cattle, 19 (30.7%) can be considered as specific for the group; among them 8 were typical for metacentric group of Y chromosome and 11 for submetacentric.     

Studies on trypanosomatid actin. I. Immunochemical and biochemical identification

In this study, the presence of actin in cultured trypanosomatids was investigated using polyclonal antibodies to heterologous actin. Polyclonal antisera to rabbit muscle actin and a monospecific anti-actin antibody react with a 43-kDa polypeptide in extracts of Trypanosoma cruzi, Herpetomonas samuelpessoai and Leishmania mexicana amazonensis on protein immunoblots. The 43-kDa polypeptide co-migrates with skeletal muscle actin and is retained within trypanosomatid cytoskeletons. Attempts to isolate H. samuelpessoai actin through DNase I affinity chromatography showed that the 43-kDa polypeptide did not bind to the column. Instead, low yields of a 47-kDa polypeptide were obtained indicating that the trypanosomatid actin displays unusual DNase I binding behavior when compared to actins from higher eukaryotes. Immunofluorescence studies confirmed that cytoskeletons retain the actin-like protein. In H. samuelpessoai, actin is localized in the region close to the flagellum, whereas in T. cruzi it is more homogeneously distributed. The data presented here show that trypanosomatid actin displays biochemical characteristics similar to actins of other protozoa.     

Haemoglobin polymorphism in Norwegian Red Cattle

By the use of isoelectric focusing in polyacrylamide gels and the Immobiline method at pH range 7.1-7.7, three haemoglobin (Hb) phenotypes were observed in Norwegian Red Cattle. Two one-band phenotypes named HbA4 and HbA6 occurred in unequal proportions in their two-band combination type with the cathodal HbA6 being the stronger. In 76 dam-offspring pairs the distribution of phenotypes were in agreement with codominant single gene inheritance. In an unselected material of 140 animals, gene frequencies were HbA4 = 0.94 and HbA6 = 0.06.     

Polymorphism of phosphoglucomutase in a German breed cattle

Haemolysates from cattle belonging to the Hochfleckvieh breed (N = 42), were studied for electrophoretic variation of phosphoglucomutase. Three phenotypes were observed which could be explained on the basis of two alleles PGMi^A and PGMi^B. The PGM'^B frequency of 0.7325 is comparatively lower than in other breeds.     

BoLA class I allele diversity and polymorphism in a herd of cattle

Major histocompatibility complex class I genes are among the most polymorphic genes characterized. The high level of polymorphism is essential for generating host immune responses. In humans, three distinct genomic loci encode human leukocyte antigen (HLA) class I genes, allowing individuals to express up to six different HLA class I molecules. In cattle, the number of distinct genomic loci are currently at least six, and the number of different bovine leukocyte antigens (BoLA) class I molecules that are expressed in individual animals are variable. The extent of allele variation within the cattle population is unknown. In this study, the number and variety of BoLA class I sequences expressed by 36 individuals were determined from full-length BoLA class I cDNA clones. Twenty distinct BoLA class I alleles were identified, with only four being previously reported. The number of expressed BoLA class I alleles in individual animals ranged between one and four, with none of the animals having an identical complement of BoLA class I molecules. Variation existed in the number of BoLA class I alleles expressed as well as the composition of expressed alleles, however, several BoLA class I alleles were found in multiple individual animals. Polymorphic amino acid sites were analyzed for positive and negative selection using the ADAPTSITE program. In the antigen recognition sites (ARS), there were eight positions that were predicted to be under positive selection and three positions that were predicted to be under negative selection from 62 positions. In contrast, for non-antigen recognition sites (non-ARS), there were three positions that were predicted to be under positive selection and 20 that were predicted to be under negative selection from 278, indicating that positive selection of amino acids occurs at a greater frequency within the antigen recognition sites.     

Prediction of breed composition in an admixed cattle population

Swiss Fleckvieh was established in 1970 as a composite of Simmental (SI) and Red Holstein Friesian (RHF) cattle. Breed composition is currently reported based on pedigree information. Information on a large number of molecular markers potentially provides more accurate information. For the analysis, we used Illumina BovineSNP50 Genotyping Beadchip data for 90 pure SI, 100 pure RHF and 305 admixed bulls. The scope of the study was to compare the performance of hidden Markov models, as implemented in structure software, with methods conventionally used in genomic selection [BayesB, partial least squares regression (PLSR), least absolute shrinkage and selection operator (LASSO) variable selection)] for predicting breed composition. We checked the performance of algorithms for a set of 40 492 single nucleotide polymorphisms (SNPs), subsets of evenly distributed SNPs and subsets with different allele frequencies in the pure populations, using F_ST as an indicator. Key results are correlations of admixture levels estimated with the various algorithms with admixture based on pedigree information. For the full set, PLSR, BayesB and structure performed in a very similar manner (correlations of 0.97), whereas the correlation of LASSO and pedigree admixture was lower (0.93). With decreasing number of SNPs, correlations decreased substantially only for 5% or 1% of all SNPs. With SNPs chosen according to F_ST, results were similar to results obtained with the full set. Only when using 96 and 48 SNPs with the highest F_ST, correlations dropped to 0.92 and 0.90 respectively. Reducing the number of pure animals in training sets to 50, 20 and 10 each did not cause a drop in the correlation with pedigree admixture.     

Haemoglobin polymorphism inGadus morhua: Genotypic differences in haematocrit

Haematocrit (erythrocyte/plasma ratio) values of the three commonHbI genotypes were recorded in two samples totalling 149 specimens of Atlantic cod (Gadus morhua L.) caught in the Trondheimsfjord, Norway, during March–April 1984. The haematocrit values were shown to depend on bothHbI genotype and sex; the females revealed higher average haematocrit values than males, and among the males theHbI-22 genotypes displayed higher average haematocrit values than the two other HbI genotypes.Contribution No. 211, Biological Station, N-7000 Trondheim, Norway     

Genetic variation within the Hereford breed of cattle

Genetic differentiation among Hereford populations from Britain, Ireland, Sweden, Canada and New Zealand together with six other beef breeds was assessed using blood type polymorphisms. Changes in the genetic structure of the British Hereford population over time were also examined. Loci surveyed were seven red cell antigen systems (A, B, C, F, L, S, Z), and two serum protein loci (transferrin and albumin). Within group variation was measured by the average expected heterozygosity, and between group relationships by genetic distance. There was significant genetic differentiation among Hereford populations from different countries. Differences between Hereford groups, however, were not as large as differences between breeds. There were also significance differences among British herds. The proportion of Canadian genes in the British 'hybrid' population was estimated to have increased from 0·42 (±0·34) in the 1970s to 0·98 (±0·11) in the 1990s. Canadian Hereford groups were found to be less heterozygous than other groups, and replacement of the British population with Canadian animals may lead to loss of variation. Breeding strategies that preserve original native genes in British Hereford populations should be considered by commercial breeders, in order to prevent the long-term loss of genetic variation within the breed.     

Dynamics of genomic architecture during composite breed development in cattle

Some livestock breeds face the challenge of reduced genetic variation, increased inbreeding depression owing to genetic drift and selection. Hybridization can reverse these processes and increase levels of productivity and adaptation to various environmental stressors. Samples from American Brangus were used to evaluate the indicine/taurine composition through nine generations (~45 years) after the hybridization process was completed. The purpose was to determine how hybridization alters allelic combinations of a breed over time when genetic factors such as selection and drift are operating. Furthermore, we explored genomic regions with deviations from the expected composition from the progenitor breeds and related these regions to traits under selection. The Brangus composition deviated from the theoretical expectation, defined by the breed association, of 62.5% taurine, showing taurine composition to be 70.4 ± 0.6%. Taurine and indicine proportion were not consistent across chromosomes. Furthermore, these non-uniform areas were found to be associated with traits that were probably under selection such as intermuscular fat and average daily gain. Interestingly, the sex chromosomes were predominantly taurine, which could be due to the composite being formed particularly in the final cross that resulted in progeny designated as purebred Brangus. This work demonstrated the process of new breed formation on a genomic level. It suggests that factors like genetic drift, selection and complementarity shift the genetic architecture into a uniquely different population. These findings are important to better understand how hybridization and crossbreeding systems shape the genetic architecture of composite populations.