Genetic structure and admixture in sheep from terminal breeds in the United States

Selection for performance in diverse production settings has resulted in variation across sheep breeds worldwide. Although sheep are an important species to the United States, the current genetic relationship among many terminal sire breeds is not well characterized. Suffolk, Hampshire, Shropshire and Oxford (terminal) and Rambouillet (dual purpose) sheep (n = 248) sampled from different flocks were genotyped using the Applied Biosystems Axiom Ovine Genotyping Array (50K), and additional Shropshire sheep (n = 26) using the Illumina Ovine SNP50 BeadChip. Relationships were investigated by calculating observed heterozygosity, inbreeding coefficients, eigenvalues, pairwise Wright’s F_ST estimates and an identity by state matrix. The mean observed heterozygosity for each breed ranged from 0.30 to 0.35 and was consistent with data reported in other US and Australian sheep. Suffolk from two different regions of the United States (Midwest and West) clustered separately in eigenvalue plots and the rectangular cladogram. Further, divergence was detected between Suffolk from different regions with Wright’s F_ST estimate. Shropshire animals showed the greatest divergence from other terminal breeds in this study. Admixture between breeds was examined using admixture , and based on cross-validation estimates, the best fit number of populations (clusters) was K = 6. The greatest admixture was observed within Hampshire, Suffolk, and Shropshire breeds. When plotting eigenvalues, US terminal breeds clustered separately in comparison with sheep from other locations of the world. Understanding the genetic relationships between terminal sire breeds in sheep will inform us about the potential applicability of markers derived in one breed to other breeds based on relatedness.     

The inheritance of blood groups in the blood group system B in cattle

The mode of inheritance of blood groups in man and animals has been a matter of discussion as long as investigations in this field have been performed.A series of aberrations from the usual transmission of genes controlling the blood groups of the system B of cattle is presented. These data offer a contribution to the assumption that the blood groups are controlled by linked genes.On leave from the Faculty of Agriculture, University of Cairo, Egypt, U.A.R.     

Blood group and protein polymorphism gene frequencies for seven breeds of horses in the United States

Gene frequencies at 20 blood group and protein polymorphism loci (A, C, D, K, P, Q, U, Al, Tf, Pi, Xk, Es, Gc, PGD, CA, Cat, PGM, AP, Hb and PHI) are given for seven horse breeds in the United States (Thoroughbred, Arabian, Standardbred, Morgan, Quarter Horse, Paso Fino and Peruvian Paso). These data are used to calculate that the battery of tests is at least 96% effective for recognizing incorrect paternity in these breeds. In addition to paternity testing, these tests can be applied to studies of breed relationships.     

Blood group and protein polymorphism gene frequencies for seven breeds of horses in the United States

Gene frequencies at 20 blood group and protein polymorphism loci ( A, C, D, K, P, Q, U, Al, Tf, Pi, Xk, Es, Gc, PGD, CA, Cat, PGM, AP, Hb and PHI ) are given for seven horse breeds in the United States (Thoroughbred, Arabian, Standard bred, Morgan, Quarter Horse, Paso Fino and Peruvian Paso). These data are used to calculate that the battery of tests is at least 96% effective for recognizing incorrect paternity in these breeds. In addition to paternity testing, these tests can be applied to studies of breed relationships.     

Frequency of hepatitis B antigen in blood donors

Routine testing of all blood donations for hepatitis B antigen by counter-immunoelectrophoresis was started in April 1971. The frequency of HBAg carriers among apparently healthy volunteer blood donors in the Toronto Centre of the Canadian Red Cross Blood Transfusion Service was 15 in 10,000 with a male:female ratio of 6:1. Excluding penitentiary inmates, the highest incidence was among young, male, non-Anglo-Saxon city dwellers.A system of notification of HBAg-positive donors was developed, through which a carrier is referred to a special clinic for clinical and pathological evaluation.A survey of hospital patients indicated an incidence of HB antigen 3.5 times that of our healthy donor population. A comparison of the number of post-transfusion hepatitis cases occurring before and after the commencement of routine testing for HBAg showed a marked reduction in reported cases in 1971.     

A survey of blood and other tissue parasites of leopard frogs Rana pipiens in the United States.

In a survey of blood and other tissue parasites from 137 leopard frogs, Rana pipiens complex, purchased from 13 commercial vendors in 8 states in the United States, Trypanosoma pipientis was found in 2 R. p. berlandieri, Toxoplasma ranae in 1 R. pipiens, Isospora lieberkuehni in 1 leopard frog, Haemogregarina magna in 44, Lankesterella minima in 3, Leptotheca ohlmacheri in 3 and microfilariae of Foleyella sp. in 6. The report of I. lieberkuehni is presumably a new host record. Haemogregarina temporariae (N?ller,, 1920) nov. comb. is established as a new combination for Nematopsis temporariae.     

Emergence and rapid transmission of SARS-CoV-2 B.1.1.7 in the United States

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Further studies on types A and B rat mtDNAs: cleavage maps and evidence for cytoplasmic inheritance in mammals.

We present here the cleavage maps of A and B rat mtDNA, examining particularly the legitimacy of two small recently reported EcoRI fragments. We find that the 0.13-kb fragment belongs in the map whereas the 0.09-kb fragment is of nonmitochondrial origin. A comparison of the types A and B maps shows that no major rearrangements have occurred since the time of the evolutionary segregation of the two DNAs. These data plus fragment patterns from other restriction enzyme digests, including those from additional enzymes which display differences between the two DNA types, provide no evidence for microheterogeneity in either of the mtDNA types, and also permit an estimate of 0.94 to 1.80% for the extent of sequence divergence of the two types. Nine enzymes yielded fragments all of which could be accurately sized leading to a reasonably accurate estimate of 15.85 kb for the size of rat liver mtDNA of either type. In a test of whether cytoplasmic inheritance is operative in mammals, reciprocal cross experiments with the two DNAs showed that only the female parental mtDNA was inherited with no evidence for the persistence of the male parental mtDNA in any of three tissues examined.     

Prion gene (PRNP) haplotype variation in United States goat breeds (Open Access publication)

Scrapie eradication efforts cost 18 million dollars annually in the United States and rely heavily upon PRNP genotyping of sheep. Genetic resistance might reduce goat scrapie and limit the risk of goats serving as a scrapie reservoir, so PRNP coding sequences were examined from 446 goats of 10 breeds, 8 of which had not been previously examined at PRNP. The 10 observed alleles were all related to one of two central haplotypes by a single amino acid substitution. At least five of these alleles (M142, R143, S146, H154, and K222) have been associated with increased incubation time or decreased odds of scrapie. To the best of our knowledge, neither S146 nor K222 has been found in any goats with scrapie, though further evaluation will be required to demonstrate true resistance. S146 was more common, present in several breeds at widely varying frequencies, while K222 was observed only in two dairy breeds at low frequency. Overall, this study provides frequency data on PRNP alleles in US goats, shows the pattern of relationships between haplotypes, and demonstrates segregation of multiple scrapieassociated alleles in several breeds not examined before at PRNP.     

The genetic map of the B system of cattle blood groups as observed in French breeds

40 cases of irregular inheritance of phenogroups in the B system of cattle blood groups, that were presumed to have arisen from single crossing-over, have been used to establish a partial genetic map of this system. In addition, the relative positions in the map of several antigenic factors were inferred from relationships observed between particular phenogroups occurring in French breeds. The tentative map thus obtained shows an overall similarity to that established by Ruiterkamp et al. (1977) in Dutch Friesian cattle. This result, in addition to other arguments, supports the hypothesis that the genetic structure of the B system of cattle blood groups is basically the same in all taurine breeds. Evidence is given, for the first time, for the occurrence in the B system of genetic events other than single crossing-over (double crossing-over or gene conversion, and possibly deletion). The rate of recombination between the genetic determinants of the terminal factors of the system, Q and I', was calculated in the progeny of some Normande bulls heterozygous for these two determinants (447 gametes); a value of 1.34 centimorgan was obtained. However complementary data indicate that 0.7 centimorgan would be a better estimate.     

The genetic map of the B system of cattle blood groups as observed in French breeds

40 cases of irregular inheritance of phenogroups in the B system of cattle blood groups, that were presumed to have arisen from single crossing-over, have been used to establish a partial genetic map of this system. In addition, the relative positions in the map of several antigenic factors were inferred from relationships observed between particular phenogroups occurring in French breeds.
The tentative map thus obtained shows an overall similarity to that established by Ruiterkamp et al. (1977) in Dutch Friesian cattle. This result, in addition to other arguments, supports the hypothesis that the genetic structure of the B system of cattle blood groups is basically the same in all taurine breeds.
Evidence is given, for the first time, for the occurrence in the B system of genetic events other than single crossing-over (double crossing-over or gene conversion, and possibly deletion).
The rate of recombination between the genetic determinants of the terminal factors of the system, Q and I', was calculated in the progeny of some Normande bulls heterozygous for these two determinants (447 gametes); a value of 1.34 centimor-gan¹ was obtained. However complementary data indicate that 0.7 centimorgan would be a better estimate.     

Breastfeeding in the United States

The breastfeeding of US infants born in 1974-76 is analyzed using data form the 1976 National Survey of Family Growth. Life table estimates of the proportion of children breastfed by duration since birth and mean breastfeeding durations are presented. The life tables reported are constructed by standard cohort table methods. To compare life tables for children of mothers in various attribute categories, generalised Wilcoxon tests are used, together with multiple classification analysis for continuation at select durations. Variables considered include mother's age at the birth, ethnicity, educational level, education by ethnicity, region of residence and the child's birth order. Findings are restricted to infants remaining with their mothers for at least 2 months following delivery and surviving as of the survey date in January-September 1976. It is found that the proportion of infants breastfed was increasing rapidly, with the highest rates found among white (39%), college-educated (56%), western (56%) mothers and lowest rates among black mothers (17%) mothers with less than a high school education (19%) and mothers living in the south (24%). By age, the highest proportions are mothers at ages 25-29 (44%), followed closely by the mothers under 25 (29%). The proportions breastfeeding were also found to be higher in urban than in rural areas (38% vs. 28%) and higher at parities 1-2 (29%). A multiple classification analysis of the factors most strongly influencing breastfeeding in 1975 shows educational level to be the strongest single predictor of breastfeeding, followed by western residence and white ethnicity. Age effects were found to correlate strongly with education. Reviewing 1971-1981 changes, the proportion of mothers with less than a college education who breastfed their children increased from 19% to 51% over the decade, while the proportion among college-educated mothers rose from 42% to 74%. For children who were breastfed, the median duration was about 4.5 months. The mean was 5.5 months, with a range from about 3.0 months among black mothers with less than a high school education, to 6.0 months among college-educated white women. The nationwide changes in breastfeeding patterns and duration may confer modest health benefits on current generations of youngsters, although not benefits that are easily measured, since human milk substitutes are routinely subjected to rigourous testing for nutritional adequacy.