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B W Kirkpatrick

Publications and source records attributed to B W Kirkpatrick.

At least 19 recordsLinked to original sources
PubMed2002

Development of microsatellite markers and comparative mapping for bovine chromosome 19.

Previous research has mapped an ovulation rate quantitative trait locus (QTL) to bovine chromosome 19. In an effort to enhance comparative mapping information and develop additional markers for refined QTL mapping, microsatellite markers were developed in a targeted approach. A bovine bacterial artificial chromosome (BAC) library was screened for loci with either known or predicted locations on bovine chromosome 19. An average of 6.4 positive BAC were identified per screened locus. A total of 10 microsatellite markers were developed for five targeted loci with heterozygosity of 7-83% in a sample of reference family parents. The newly developed markers were typed on reference families along with four previously mapped marker loci and used to create a linkage map. Comparison of locus order between human and cattle provides support for previously observed rearrangement. One of the mapped loci myotubularin related protein 4 (MTMR4) potentially extends the proximal boundary of a conserved linkage group.

Animals↗
PubMed2002

Consensus and comprehensive linkage maps of bovine chromosome 24.

This study describes development of a consensus genetic linkage map of bovine chromosome 24 (BTA24). Eight participating laboratories contributed data for 58 unique markers including a total of 25 409 meioses. Eighteen markers, which were typed in more than one reference population, were used as potential anchors to generate a consensus framework map. The framework map contained 16 loci ordered with odds greater than 1000:1 and spanned 79.3 cM. Remaining markers were included in a comprehensive map relative to these anchors. The resulting BTA24 comprehensive map was 98.3 cM in length. Average marker intervals were 6.1 and 2.5 cM for framework and comprehensive maps, respectively. Marker order was generally consistent with previously reported BTA24 linkage maps. Only one discrepancy was found when comparing the comprehensive map with the published USDA-MARC linkage map. Integration of genetic information from different maps provides a high-resolution BTA24 linkage map.

Animals↗
PubMed2002

Indirect prediction of herd life in Guernsey dairy cattle.

Production and type data were used to investigate the relationships of these traits with herd life data in US Guernsey cows that calved from 1985 through 1990. Two definitions of herd life were used: actual days from birth to disposal (true herd life) and herd life adjusted for milk production (functional herd life). Genetic parameters were calculated with data from cows that had an opportunity to reach 84 mo of age (n = 18,725). Linear type traits were preadjusted for stage of lactation and age at classification. True herd life was preadjusted for age at first calving and for functional herd life, within herd-year quartile ranking for milk yield. The (co)variance components for true and functional herd life, milk, fat, protein, and 15 linear type traits were estimated with multiple-trait REML in an animal model. Heritability estimates for true and functional herd life were 0.12 for both traits. Estimated genetic correlations of herd life with body size traits were from -0.14 to -0.29, with feet and leg traits were from -0.10 to 0.06, and with udder traits were from -0.09 to 0.24. These correlation parameters were used for indirect prediction of herd life from available production and type information in Guernseys.

Aging↗
PubMed2001

Twinning rates for North American Holstein sires.

Calving data of North American Holsteins were analyzed using a linear sire model and a threshold sire model to estimate fixed effects and sire predicted transmitting abilities (PTA) for twinning rate. The data were 1,324,678 births of 37,174 sires of cows from the National Association of Animal Breeders (NAAB) calving ease database. All twins were assumed to be dizygotic. Triplets were not included in the analysis. The twinning rate was 5.02%. The sire model included relationships among sires and fixed effects of herd-years, season, parity, and sire groups. Different estimates of heritability due to models and restrictions on data have been demonstrated. Heritability estimates for the sire of the cow effect were 2.10% by the linear model analysis and 8.71% by the threshold model analysis. Sire PTA for twinning rate ranged from 1.6 to 8.0%. Mean incidence of twins increased from first to fifth and later parities: 1.63, 5.22, 6.66, 7.19, and 7.19%, respectively. Some changes with season were also evident. The incidence of twins was highest in April to June, at 5.88%, and lowest in October to December, at 4.23%. Sire group effects showed that sires born after 1990 had a higher incidence of twins than sires born before 1990. The mean twinning rate for sires born before 1980 was 4.55% compared with a mean of 5.58% for sires born after 1991. Characteristics of individual sire evaluations are discussed. Ample opportunity exists to change the incidence of twins in the Holstein population. Sire selection can be used to reduce the incidence of twins and also the increased cost of production associated with twins. From a national perspective, a reduction in the incidence of twin births can result in a saving of as much as $55 million per year.

Animals↗
PubMed2000

Mapping quantitative trait loci for bovine ovulation rate.

An elite, three-generation family from the USDA Meat Animal Research Center twinning population was examined for evidence of ovulation rate quantitative trait loci (QTL). This work was both a continuation of previously reported results suggesting evidence for ovulation rate QTL on bovine Chromosome (Chr) 7 and an extension of a genome-wide search for QTL. Additional markers were typed on Chr 7 to facilitate interval mapping and testing of the hypothesis of one versus two QTL on that chromosome. In addition, 14 other informative markers were added to a selective genotyping genome screening of this family, and markers exhibiting nominal significance were used to identify chromosomal regions that were then subjected to more exhaustive analysis. For Chr 7, a total of 12 markers were typed over a region spanning the proximal two-thirds of the chromosome. Results from interval mapping analyses indicated evidence suggestive of the presence of QTL (nominal P<0.00077) within this region. Subsequent analysis with a model postulating two QTL provided evidence (P<0.05) for two rather than one QTL on this chromosome. Preliminary analysis with additional markers indicated nominal significance (P<0.05) for regions of Chrs 5, 10, and 19. Each of these regions was then typed with additional markers for the entire three-generation pedigree. Significant evidence (P<0.000026) of ovulation rate QTL was found for Chrs 5 and 19, while support on Chr 10 failed to exceed a suggestive linkage threshold (P>0.00077).

Animals↗
PubMed2000

Consensus and comprehensive linkage maps of bovine chromosome 7.

The objective of this project was to integrate the currently available linkage maps for bovine chromosome 7 (BTA7) by combining data sets from eight research groups. A total of 54 unique markers were typed in eight pedigrees. Multilocus linkage analysis with CRI-MAP produced a bovine chromosome 7 consensus framework map of 27 loci ordered with odds greater than 1000:1. Furthermore, we present a bovine chromosome 7 comprehensive map integrating 54 loci. The locus order is in general agreement with the recently published linkage maps except for one discrepancy. The order of loci BM9289, BMS713, and ILSTS001 was reversed in the consensus framework map relative to the published USDA-MARC bovine chromosome 7 linkage map.

Animals↗
PubMed1999

A comparative linkage and physical map of bovine chromosome 24 with human chromosome 18.

Polymorphic microsatellites have been developed in the vicinity of nine genes on bovine chromosome (BTA) 24, all orthologous to genes on human chromosome (HSA) 18. The microsatellites have been isolated from bacterial and yeast artificial chromosome clones containing the genes. A linkage map was developed including these polymorphic markers and four anonymous, published microsatellites. Yeast artificial chromosomes containing six of these genes have also been mapped using fluorescent in situ hybridization (FISH), thereby tying the linkage map together with the physical map of BTA24. Comparing gene location on HSA18 and BTA24 identifies four regions of conserved gene order, each containing at least two genes. These genes identify six regions of conserved order between human and mouse, two more than in the human-bovine comparison. The breakpoints between regions of conserved order for human-bovine are also breakpoints in the human-mouse comparison. The centromere identifies a fifth conserved region if the BTA24 centromere is orthologous with the HSA18 centromere.

Animals↗
PubMed1998

Identification of quantitative trait loci for prolificacy and growth in mice.

Marker-quantitative trait locus (QTL) linkage was evaluated in F2 intercross and backcross mouse populations derived from stocks differing dramatically in prolificacy and mature weight. A highly prolific outbred Quackenbush-Swiss mouse line, or an inbred line derived from it (16.62 +/- 0.22 and 14.64 +/- 0.27 pups per litter, respectively) were used as one of the grandparents in these populations. The less prolific C57BL/6J inbred mouse line (6.67 +/- 0.37 pups per litter) was used as the other grandparent. Linkage was evaluated in a three-step process that involved selective genotyping of F2 intercross progeny representing extremes for prolificacy, genotyping of the full F2 for chromosomal regions potentially associated with prolificacy, and genotyping of the backcross for genomic regions significantly associated with prolificacy in the F2. Segments of Chromosomes (Chrs) 2 and 4 were significantly (P < 0.05, experiment-wise error rate) associated with prolificacy, and LOD scores suggestive of linkage were observed for litter size on Chr 9 and growth on Chrs 4 and 11. Existence of growth QTL was also supported by marker effects that were significant (P < 0.05) or approaching significance (P < 0.10) in the backcross. Additive litter size QTL effects ranged from 0.56 to 0.79 pups per litter, and dominance deviations ranged from -0.56 to 1.19 pups per litter, suggesting overdominance as a possible mode of gene action in some cases. The observation of pleiotropic or linked QTL for growth and prolificacy corresponds well with results from many selection experiments identifying positively correlated responses to selection for these two traits.

Analysis of Variance↗
PubMed1998

Report of the first workshop on the genetic map of bovine chromosome 1.

A report of the first workshop on the genetic map of bovine chromosome 1 (BTA1) is presented. Five laboratories contributed 31,962 informative meioses from 70 loci. Thirty-two loci which had been typed by at least two laboratories were used to construct a framework genetic map with a likelihood ratio support of at least 1000:1 for locus order. The resulting sex-averaged framework map contained 26 loci and spanned 163.6 CM. The lengths of the female and male maps were 159.5 CM and 165.3 CM, respectively, and there was evidence for an expansion in the telomeric one-third of the male map. Of the four cases where order for closely linked loci differed among the maps produced for each of the contributing laboratories, a consensus order was obtained for three in the framework map. The average genetic distance between framework loci on the sex-averaged map was 6.3 CM.

Animals↗
PubMed1997

Comparative linkage mapping of human chromosome 13 and bovine chromosome 12.

A comparative linkage map of human chromosome 13 and bovine chromosome 12 was constructed using eight polymorphic microsatellite markers associated with six specific genes. Linkage of these was also examined relative to five previously mapped anonymous microsatellite markers. Seven gene-linked markers were developed from bovine large-insert genomic clones containing one of five genes of interest (serotonin receptor subtype 2, fms-related tyrosine kinase, coagulation factor 10, retinoblastoma susceptibility gene, collagen type IV alpha 1), and one additional marker was developed from a microsatellite resident within an intron of the bovine dopachrome tautomerase gene. Four of these loci were previously assigned to bovine chromosome 12 by analysis of a somatic cell hybrid panel. This study provides linkage information for examining gene order in this conserved synteny group. The comparative linkage mapping results indicate that the q arm of human chromosome 13 is almost entirely conserved in bovine chromosome 12. One intrachromosomal rearrangement was detected in this linkage group relative to human, and this rearrangement was confirmed by fluorescence in situ hybridization results.

Animals↗
PubMed1997

Relationship of growth hormone and insulin-like growth factor-1 genotypes with growth and carcass traits in swine.

The contribution of chromosomal regions linked to growth hormone (GH) and insulin-like growth factor-1 (IGF-1) loci to variation in preweaning average daily gain, postweaning average daily gain (ADG), 10th rib backfat, loin-eye area and muscle pH were evaluated. Offspring of four purebred sires (A-D; n = 150, 195, 148 and 136, respectively) and two cross-bred sires (E and F; n = 157 and 145, respectively) were genotyped initially with GH and IGF-1 markers. When results of single marker analysis suggested possible linkage with a quantitative trait locus (QTL), additional flanking markers were typed for the family and interval mapping was performed. Growth hormone genotype was not associated with the traits evaluated in the study. Evidence suggestive of linkage was found for IGF-1 genotype and ADG in one sire family (lod = 2.3) where differences were 0.032 +/- 0.01 kg/day for alternative sire alleles. Evidence for a putative ADG QTL was greatest in the interval between IGF-1 and Sw1071. A similar genomic region has been associated with growth variation in mice; however, QTL mapping precision in the current study is insufficient to establish similarity.

Alleles↗
PubMed1997

Synteny mapping of four genes from the short arm of human chromosome 19 to bovine chromosome 7.

Four genes on the short arm of human chromosome 19 (HSA 19p) were assigned to bovine chromosome 7 (BTA 7) using a bovine x rodent somatic hybrid cell panel. These four genes were cartilage oligomeric matrix protein (COMP), lymphoblastic leukemia derived sequence 1 (LYL1), lysosomal alpha-mannosidase (MANB), and RAS oncogene family member RAB3A. Bovine sequence tagged sites were developed for the four genes and used for screening a bovine x rodent somatic cell panel. All four genes were mapped to bovine synteny group U22 (BTA 7) with a correlation coefficient of 0.901-1.000. This study confirms that the centromeric region of BTA 7 is conserved with HSA 19p.

Animals↗
PubMed1997

Mapping genomic regions associated with growth rate in pigs.

The objective of this study was to identify genomic regions associated with postweaning average daily gain (ADG) in swine. Two families were produced using sires obtained from the cross of lines divergently selected for high and low growth rate. Sires were mated to 29 unrelated dams that produced 124 and 115 offspring. Average daily gain was recorded for every individual; mean ADG was .593 +/- .007 kg/d and .619 +/- .009 kg/d in the two families. Selective genotyping was performed as a prescreening procedure to identify genomic regions potentially associated with ADG. A total of 75 genetic markers were used between both families. Markers identified as nominally significant (P < .05) in an individual marker analysis were subsequently typed in all individuals. Markers still nominally significant (P < .05) after analysis with the complete family were then reevaluated together with flanking markers in an interval mapping analysis. A single region on chromosome 3, flanked by markers Sw2429 and Sw251, for the second family had a logarithm of the odds score of 2.9, which is suggestive of linkage with a quantitative trait locus for ADG. Differences were .033 +/- .009 kg/d between individuals inheriting alternative paternal alleles for Sw251, which was the most significant marker.

Alleles↗
PubMed1996

Exploiting dinucleotide microsatellites conserved among mammalian species.

Dinucleotide microsatellites are useful for gene mapping projects. Depending upon definition of conservation, published estimates of dinucleotide microsatellite conservation levels vary dramatically (30% to 100%). This study focused on well-characterized genes that contain microsatellites in the human genome. The objective was to examine the feasibility of developing microsatellite markers within genes on the basis of the assumption of microsatellite conservation across distantly related species. Eight genes (Gamma-actin, carcinoembryonic antigen, apolipoprotein A-II, cardiac beta myosin heavy chain, laminin B2 chain, MHC class I CD8 alpha chain, c-reactive protein, and retinoblastoma susceptibility protein) containing large dinucleotide repeat units (N > or = 15), complete genomic structure information, and homologous gene sequences in a second species were selected. Heterologous primers were designed from conserved exon sequences flanking a microsatellite motif. PCR products from bovine and porcine genomic DNA were tested for the presence of microsatellite sequences by Southern blot hybridization with biotin-labeled (CA)12 oligonucleotides. Fragments containing microsatellites were cloned and sequenced. Homology was verified by sequence comparisons between human and corresponding bovine or porcine fragments. Four of sixteen (25%) cross-amplified PCR products contained dinucleotide repetitive sequences with repeat unit lengths of 5 to 23. Two dinucleotide repetitive sequences showed microsatellite length polymorphism, and an additional sequence displayed single-strand conformational polymorphism. Results from this study suggest that exploitation of conserved microsatellite sequences is a useful approach for developing specific genetic markers for comparative mapping purposes.

Animals↗