Transferrin polymorphism in Herdwick sheep

The transferrin system in Herdwick sheep, bred at Compton, was investigated with special reference to the susceptibility of the flock to experimentally produced scrapie. No significant correlations were observed between susceptibility and transferrin phenotypes.     

Transferrin polymorphism in Central Thailand

Summary Transferrin (Tf) variants were determined in the serum of 1385 persons from the districts of Nakon Thai, Wang Thong, Bang Rakam, Bang Krathum, Prom Piran, Wat Bot, and Phitsanolok in Central Thailand. Besides the common phenotype CC, we also observed CD₁, CD_Chi, and D_ChiD_Chi variants.This publication is part of the thesis of H. H. Dahm, submitted to the Medical Faculty, University of Freiburg.Supported by the Deutsche Forschungsgemeinschaft and the Stiftung VW.     

Transferrin types and reproduction in sheep

Transferrin types were determined for flocks of Finnish Landrace, Clun Forest, Soay and Merino sheep and gene frequencies were calculated. Analysis of ratios of transferrin types in segregating matings of Finnish Landrace and Clun Forest revealed a significant excess of heterozygotes in matings of heterozygous rams with heterozygous and with homozygous ewes. In Finnish Landrace, matings of sheep homozygous for Tf ^c to those heterozygous for Tf ^C gave a significant excess of homozygous male lambs and heterozygous female lambs. Finnish Landrace ewes of transferrin type BD had smaller litters than ewes of other types.     

Genetic markers in Herdwick sheep: no correlation with succeptibility or resistance to experimental scrapie

Genetic markers were studied in Herdwick sheep, bred at Compton, with special reference to genetically selected lines which differ in susceptibility or resistance to experimentally produced scrapie. There were no correlations between susceptibility to the disease and albumin, pre-albumin, esterase and haemoglobin phenotypes, and between reduced glutathione levels and alpha-mannosidase isoenzymes, the latter possibly representing a previously undescribed genetic marker in sheep.     

Transferrin in fetal sheep cerebrospinal fluid and plasma during gestation

1. Transferrin concentrations in fetal sheep CSF and plasma have been estimated between 31 and 125 days gestation and in the adult, using a radial immunodiffusion assay. 2. The plasma concentration was lowest (183 +/- 35 mg/100 ml) in the earliest fetuses examined (31 days). It increased to over 350 mg/100 ml by 35 days; thereafter it was around the adult value (580 mg/100 ml). 3. In CSF the transferrin concentration increased from 43 +/- 10 mg/100 ml at 31 days to a maximum of 163 +/- 14 mg/100 ml at 40 days gestation after which it decreased considerably to 6.1 +/- 0.7 mg/100 ml at 125 days and was even lower in the adult (1.1 +/- 0.2 mg/100 ml). 4. CSF: plasma ratios for transferrin especially when compared with those of other plasma proteins, are not compatible with passive leakage of protein from blood to CSF in the developing brain. The results may be explained by specific transfer of proteins into CSF but synthesis by the choroid plexus or brain has not been excluded.     

Transferrin and haemoglobin polymorphism in domesticated goats in the USA

The distribution of transferrin (Tf) and haemoglobin (Hb) polymorphisms in five goat breeds in the USA is reported. Two Tf types, A and B, were identified. A significant difference in frequency (P less than 0.05) was observed only between the Spanish and Alpine goats. Haemoglobin beta-globin variants, Hb beta A, Hb beta D and Hb beta E were observed with isoelectric focusing at pH ranges 5-8 and 6.7-7.7. Hb beta D was not found in the Alpine and Angora breeds. Haemoglobin allelic frequencies varied widely and differed significantly (P less than 0.05) among breeds.     

Glucosephosphate isomerase polymorphism in sheep

Two types of glucosephosphate isomerase (GPI) are described for the first time in sheep. Type T produced a 3-band pattern on polyacrylamide gel electrophoresis of serum samples, whereas type M produced a pattern of 5-7 bands. When 23 Scottish Halfbred ewes showing type T were mated to 3 Suffolk rams showing type M, their 32 offspring had frequencies of 0.72 and 0.28 for T and M respectively. There was no conclusive evidence that the types were controlled by codominant alleles or by simple Mendelian inheritance and neither was sex-linked. The frequency of the rarer type (M) was sufficiently high to provide conclusive evidence of true enzyme polymorphism.     

Transferrin polymorphism and serum proteins of some British deer

Polymorphism of serum proteins has been described in a number of animals. The complexity of the phenotype pattern and the number and relative frequencies of the variants differ from species to species. Within a species, the variants have sometimes been found to characterize breeds and races. In this investigation the variants of transferrin in the serum proteins of three British deer, Red (Cervus elaphus L.), Fallow (Dama dama (L)) and Sika (Cervus nippon Temminck) have been studied and compared with those of other wild and domesticated ruminants for which data are available. In Red deer their distribution differed in samples from Rhum and Braemar. On Rhum, their distribution did not indicate any significant genetic differences between the stock in the six areas onto which the population appeared to be hefted. However, there appeared to be a difference corresponding to the main east and west division of the island, the significance of which is not apparent.     

Genetic polymorphism in Spanish Merino sheep

A Spanish Merino sheep population is characterized, for the first time, according to its frequencies for a total of nine polymorphic loci: three blood group factor systems, A, B and C, and the following red cell or serum polymorphisms: haemoglobin (Hb), carbonic anhydrase (CA), 'X protein', transferrin (Tf), arylesterase (EsA) and albumin (Al). Another locus, amylase (Am), did not show polymorphism.     

'Malic enzyme' polymorphism in sheep erythrocytes

Malic enzyme or malate dehydrogenase (NADP +). E.C.I.I.I.40. catalyses the reaction:
L-malate + NADP⇄2 pyruvate + CO₂+ NADPH
Baker & Manwell (1977), in a survey of a number of different enzymes reported that 'malic enzyme' was polymorphic in the erythrocytes and certain other tissues of sheep, and indicated that it would be a potentially useful new genetic marker for this species. This paper confirms the existence of the polymorphism in sheep erythrocytes and presents inheritance and breed data.     

Transferrin polymorphism in Central Amazon populations of pescada, Plagioscion squamosissimus

Blood plasma of 253 specimens from eight population samples of the sciaenid fish, pescada (Plagioscion squamosissimus), caught from four sites in the Central Amazon, was tested for molecular variants of transferrin. Starch gel electrophoresis was used to distinguish six species of transferrin molecules; 12 of the 21 theoretically possible genotypes were found. There were highly significant departures from genetic equilibrium in seven of the eight population samples (chi-square (chi(2)) test for Hardy-Weinberg expectations) due to an excess of homozygotes and a corresponding deficiency of heterozygotes. A dendrogram based on UPGMA cluster analysis of genetic distances at the transferrin gene locus, estimated among the population samples and statistical analyses of the distribution of Tf allele frequencies, indicated three genetically discreet sub-populations of P. squamosissimus. The three sub-populations, "Careiro/Iranduba", "Coari" and "Tefe", were found to have high frequencies of alleles Tf(2), Tf(4) and Tf(3), respectively. This genetic instability may be attributed to genetically discreet "allopatric stocklets", which diverged during past isolation.     

Transferrin (Tf) polymorphism in wild rabbit, Oryctolagus cuniculus

Evidence for two new alleles (TfC and TfD) at the transferrin locus (Tf) in wild rabbit, Oryctolagus cuniculus, is presented. Blood samples were collected in Continental Portugal (178 individuals), and in the Azores Islands of Terceira (52) and S. Miguel (59). The frequency of TfA, which is the only allele detected up to now in domestic rabbits, varied from 0.20 +/- 0.13 to 0.95 +/- 0.05 in the populations sampled in Continental Portugal. In the island populations sampled the frequency of TfA was greater than 0.8.     

Purine nucleoside phosphorylase polymorphism in sheep erythrocytes

A polymorphism of purine nucleoside phosphorylase is described in sheep erythrocytes. Two isozymes were distinguished electrophoretically, one with high activity (NP-1) and one with low activity (NP-2). Breeding data suggest that the two isozymes are the product of two codominant alleles, NP¹and NP². The K_m's for inosine did not differ between NP-1 and NP-2; however, NP-2 had a lower pH optimum and was relatively unstable when incubated at 48 C.Contribution No. 421-J, from the Department of Pathology, Kansas Agricultural Experiment Station, Manhattan, Kansas. Supported in part by USPHS Grants HL-70119 and HL 12072.     

Domesticated behavior in sheep. Role of behavioral polymorphism in the regulation of stress reactions in sheep]

The relationship between behavioral polymorphism and the variation for the function of the hypothalamic-pituitary-adrenocortical axis (HPAA) was studied in the meat-and-wool (n = 447) and Altaian fine-fleece (n = 45) sheep breeds under production farm conditions. The behavior studied included negatively associated reactions: feeding reactions and defensive reactions in relation to human. In sheep, the intrapopulation variation for the stress level of corticosteroids depended on the effect of behavior, the type of stimulus, and the interaction between these two factors and correlated with the behavior phenotype (r varied from -0.551 to -0.226). In the stress responses to either 24-h starvation or lamb weaning, hormonal reactions were similar in wild-type sheep that have clearly marked defensive reactions and in the sheep of the domestic phenotype that was contrasted to the wild type. In the stress responses to isolation from the herd, transportation, and competition for food, hormonal reactions were stronger in the wild type than in the domestic phenotype; alternatively, in the stress response to being kept in cages in pairs, hormonal reaction was stronger in the domestic phenotype than in the wild type. In the sheep that were placed in cages, a single playing of tape-recorded anxiety signals caused the motivational or emotional stress that was characterized by an unusually long latent period of the progressive HPAA reaction and its subsequent chronic course (up to 9 days). Animals of contrasted behavioral phenotypes differed in the course of the HPAA reaction. Heritable behavioral polymorphism and interaction between behavior and the type of stimulus are the regulation factors in the expression and variability of stimulus-specific reactions of HPAA. Behavior can serve as the genetic marker for individual features of HPAA functioning in the stress response of sheep.     

DNA polymorphism at the casein loci in sheep

By using seven endonucleases and four bovine cDNA probes specific for alpha S1-, alpha S2-, beta-, and kappa-casein genes, nine restriction fragment length polymorphisms (RFLPs) have been found in the sheep orthologous DNA regions. In contrast to the low level of variation observed at the protein level, these DNA polymorphisms determine a high level of heterozygosity and, therefore, represent useful tools for genetic analyses since they can also be obtained without the need for gene expression. In fact, informative matings suggest that in sheep, as in cattle, the four loci are linked.     

Transferrin variants in sheep: separation and characterization by polyacrylamide gel electrophoresis and isoelectric focusing

Isoelectric focusing with carrier ampholytes in ultrathin polyacrylamide gels and polyacrylamide gel electrophoresis in a discontinuous buffer system were used for the separation of sheep transferrin variants. For identification of the different iron-binding sites of transferrin a stepwise urea gradient, different degrees of iron saturation and double one-dimensional electrophoresis were used. Isoelectric focusing results in an increased resolution of the Fe0-transferrin, Fe1-transferrin and Fe2-transferrin region. At the level of Fe0-transferrin and Fe1-transferrin the variants I, A, G, B, C, D, M, E, Q, P can be identified. The method is especially suitable for genetic studies. For screening purposes up to 108 samples can be separated within one run in an ultrathin gel.