摘要:

SummaryVariation at 22 gene loci was investigated in a flock of Australian Merino sheep using restriction fragment length polymorphism (RFLP) analysis. Polymorphism was observed at 20 loci, including loci for wool keratin, hormone and immunoglobulin light chain genes. Eleven loci yielded unambiguous genotypes suitable for population data analysis. Average heterozygosity, determined from these and two monomorphic loci, was estimated as 0.107 (SE = 0.024). Average heterozygosity excluding all monomorphic data was estimated as 0–377 (SE = 0.031), which is comparable with human RFLP heterozygosities for loci chosen in the same way that we selected sheep loc

ISSN:0268-9146    

DOI:10.1111/j.1365-2052.1996.tb00482.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

SummaryUntil now the genetic linkage map in chicken has been based mainly on random genomic markers. The addition of expressed sequence tags (ESTs) to the genetic linkage maps is becoming more important because ESTs can form the basis for comparative mapping studies. This may be helpful for the detection of candidate genes for quantitative trait loci (QTLs).In our study we used a (TG)13repeat as probe for the detection of microsatellites in a chicken brain cDNA library. After hybridization 0.15% of the cDNA clones gave a positive signal. The cDNA complexity of the library was high; of the 90 cDNA clones that were sequenced 60 occurred only once. For 29 clones primer sets for the polymerase chain reaction could be developed. Twenty‐one microsatellites were polymorphic on one or more of the test panels and 15 markers could be mapped on either or both of the international reference families. Because sequence homology between chicken and mammalian cDNAs is sometimes low it was difficult to assess the level of sequence homology that indicated a true homologous transcript. In our study seven cDNA clones, of which three could be mapped, showed a relatively high percentage of sequence homology with sequences found in other species. Because sequencing and mapping of expressed sequence tags in human and mouse is progressing very rapidly, it is predicted that further information will soon be readily available. Therefore, increasing the number of expressed sequences on the chicken genetic linkage map will be of value for comparative mapping studies in the near futur

ISSN:0268-9146    

DOI:10.1111/j.1365-2052.1996.tb00483.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

SummaryMarker‐assisted selection (MAS) uses genetic marker genotypes to predict an animal's production potential and will provide additional selection information for progeny testing. With the discovery of highly polymorphic microsatellite markers, the tools now exist to begin the search for economic trait loci (ETL), which is the first step toward MAS. The objective of this study was to identify ETL for somatic cell score in an existing Holstein population. Using the granddaughter design, sons from seven grandsire families were genotyped with 20 autosomal microsatellites from five chromosomes (4, 8, 13, 17, 23), with an emphasis on chromosome 23, which is the location of the bovine major histocompatibility complex (BoLA). Selective genotyping was used to reduce the number of genotypes required, in which the 10 highest and 10 lowest sons from the phenotypic distribution curve were tested (140 sons in seven families). One marker (513), located near BoLA, showed evidence of an ETL in three of five polymorphic families. Additional sons were genotyped from the five families to estimate the effect and to compare selective and ‘complete’ genotyping. Both methods detected an ETL at marker 513, but in different families. This study provides evidence of the usefulness of microsatellite markers and the granddaughter design in the detection of ETL; however, additional markers need to be evaluated to determine the usefulness of selective genotyping. Based on the results from the 20 studied markers, the most likely position of a somatic cell score ETL lies near marker 513, located on chromoso

ISSN:0268-9146    

DOI:10.1111/j.1365-2052.1996.tb00484.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

SummaryTrinucleotide (AGC)nmicrosatellites are found as 3′ tails of the artiodactyl short interspersed nuclear element (SINE) A‐dimer. We describe a polymerase chain reaction (PCR)‐based method for the construction of a plasmid library enriched for SINE (AGC)nmicrosatellites. By amplifyingSau3AIinserts with a conserved SINE primer and a flanking vector primer, a 35‐fold enrichment of (AGC)nmicrosatellites over a conventional genomic library was obtained. The SINE primer was used for both sequencing of AGC‐containing inserts and analysis of polymorphism. Twenty‐three unique reverse primers were synthesized and used on bovine genomic DNA, 21 producing PCR products of expected size. Five polymorphic (AGC)nmicrosatellites with 2–4 alleles each were characterized. Allele sizes differed by a 3 bp motif and lacked the stutter bands associated with dinucleotide repeats. A tendency of increased polymorphism for longer AGC repeat arrays was observed. High stringency selection for positive clones containing eight or more AGC repeats can thus facilitate the isolation of polymorphic (AGC)nmicrosatellites, Enrichment for (AGC), microsatellites by SINE‐vector PCR can be applied to other bovidae species, such as sheep or goat, containing the artiodacty

ISSN:0268-9146    

DOI:10.1111/j.1365-2052.1996.tb00485.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

SummaryThe following loci, on human chromosome 13, have been newly assigned to sheep chromosome 10 using chromosomally characterized sheep‐hamster cell hybrids: gap junction protein, beta 2, 26 kDa (connexin 26) (GJB2); gap junction protein, alpha 3, 46 kDa (connexin 46) (GJA3), and esterase D/formylglutathione hydrolase (ESD). This assignment of ESD is consistent with comparative mapping evidence, but not with an earlier report of it on sheep chromosome 3p26‐p24. Cell hybrid analysis confirmed the location of another human chromosome 13 locus, retinoblastoma 1 (including osteosar‐coma) (RBI), and the anonymous ovine genomic sequence RP11 on sheep chromosome 10. Isotopicin situhybridization was used to regionally localize RP11 on to sheep 10q15‐q22. The location of microsatellites AGLA226, OarDB3, OarHH41, OarVH58, and TGLA441, previously assigned to sheep chromosome 10 by linkage analysis, was confirmed by polymerase chain reaction using the cell hybrid panel. These mapping data provide further evidence that sheep chromosome 10 is the equivalent of cattle chromosome 12, and that these chromosomes show extensive conserved synteny with human chromo

ISSN:0268-9146    

DOI:10.1111/j.1365-2052.1996.tb00486.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

SummaryA comprehensive linkage map, including 236 linked markers with a total sex‐average map length of about 2300 cM, covering nearly all parts of the pig genome has been established. Linkage groups were assigned to all 18 autosomes, the X chromosome and the X/Y pseudoautosomal region. Several new gene assignments were made including the assignment of linkage group U1 (EAK‐HPX) to chromosome 9. The linkage map includes 77 type I loci informative for comparative mapping and 72in situmapped markers physically anchoring the linkage groups on chromosomes. A highly significant heterogeneity in recombination rates between sexes was observed with a general tendency towards an excess of female recombination. The average ratio of female to male recombination was estimated at 1–4:1 but this parameter varied between chromosomes as well as between regions within chromosomes. An intriguing finding was that blood group loci were overrepresented at the distal ends of linkage g

ISSN:0268-9146    

DOI:10.1111/j.1365-2052.1996.tb00487.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

SummaryThe bovine MHC class IIBoLA‐DRB3*2A has an amino acid deletion of unknown function at codon 65 in the second exon, which codes for the antigen‐binding site. Sequence‐specific oligonucleotides were designed based on published nucleotide sequences on BoLA‐DRB3 alleles, and used to detect this deletion in 51 Hereford cattle. Probes 65+ and 65‐ detect the presence or absence of codon 65 respectively. Oligonucleotide probes were labelled with Digoxigenin (DIG), hybridized to dot blots of BOLA‐DRB3 exon 2 polymerase chain reaction (PCR) product, and detected by chemiluminescence. Of the 51 animals screened, two were homozygous and 11 were heterozygous for the deletion at codon 65. The methodology described here provides the necessary tools to screen rapidly for this deletion in a large number of animals in order to study its effect on antigen binding and immu

ISSN:0268-9146    

DOI:10.1111/j.1365-2052.1996.tb00488.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

SummaryDegenerate primers based on human and mouse obesity gene (OBS) sequencing data were used in the reverse transcriptase‐polymerase chain reaction (RT‐PCR) of total RNA from pig white adipose tissue. Both strands of the resultant pig‐ specific 325 bp DNA fragment were sequenced. Comparison of the obtained sequence with known sequences revealed an 86% identity with the human and 84% identity with the mouse OBS cDNA. The OBS gene was physically mapped to pig chromosome 18 by PCR analysis of somatic cell hybrids, using pig‐specific primers. This result is consistent with the recent assignment of the human OBS gene to chromosome 7 and the observation made by comparative mapping that by using a human chromosome 7 specific library two segments of conserved synteny were detected on porcine chromosomes 9 and 18. We conclude the border of conserved synteny to be in the 7q31‐7q32 region of the human c

ISSN:0268-9146    

DOI:10.1111/j.1365-2052.1996.tb00489.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

SummaryThe pedigree origin of a base pair substitution in the horse muscle sodium channel gene that confers susceptibility to the muscle disease hyperkalemic periodic paralysis (HYPP) was investigated with a set of 978 Quarter Horses. The horses were chosen at random, based on a collection of blood samples taken between 1989 and 1991 to meet parentage testing requirements, primarily but not exclusively from breeding stallions. The frequency of Quarter Horses positive for the base pair substitution, all heterozygotes, was 4‐4%, which corresponds to an allelic frequency of 0.02. All horses positive for the gene traced to a single previously identified stallion as first, second or third generation descendants. A higher frequency of the HYPP susceptibility trait than expected by random occurrence was found among his descendants in this stud

ISSN:0268-9146    

DOI:10.1111/j.1365-2052.1996.tb00490.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

SummaryA polymerase chain reaction (PCR)‐based method for detection of a MspI‐restriction fragment length polymorphism (RFLP) in the bovine ornithine decarboxylase gene was developed, and the allele frequencies of the polymorphism in two groups of Holstein bulls representing progeny‐tested bulls during the 1950s‐1960s and 1980s, respectively, were estimated. The frequencies of the MspI(‐) allele were 0.229 and 0.077 and that of MspI(+) were 0.771 and 0–923 in the progeny‐tested bulls of the 1950s‐1960s and 1980s, respectively. The difference in allele frequencies between the two groups was statistically significant (P<0.005). Genetic drift could be responsible for the changes in allele frequencies; however, it could also be possible that selection for milk production was associated with the changes of the allele frequencies in the two b

ISSN:0268-9146    

DOI:10.1111/j.1365-2052.1996.tb00491.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY