Search

Functional melanocytes in the epidermis are required for cutaneous pigmentation in cattle. In spotted cattle variations in the size of pigmented sectors are of interest to animal researchers, as it is believed that those with a higher proportion of white coat absorb less solar radiation. The proportion of unpigmented coat was determined from photographs of German Simmental and Holstein bulls. The receptor tyrosinase kinase (KIT) locus is associated with depigmentation phenotypes in mice, humans and pigs, and it is suggested that KIT is a candidate gene for the degree of spotting in cattle.

The origin of Ovis aries, the modern domestic sheep, is still uncertain. Mitochondrial DNA (mtDNA) from European, African and Asian sheep breeds was assayed for restriction fragment length polymorphisms (RFLP) to investigate the origins and phylogenetic relationships of domestic sheep. Two major domestic sheep lineages were apparent in the branches containing mouflon and domestic sheep. Asian and European domestic sheep lineages were found to differ by 4.43%, with the mouflon sequence diverging by 4.52% from the Asian type, but just 1.36% from the European type. This suggests that some modern domestic sheep and European mouflon have a common ancestor.

Inhibins and activins were examined using restriction fragment length polymorphism data for linkage mapping.

The analysis of 16 paternal half-sib families of the Holstein breed with 872 sons and 264 genetic markers is studied to detect QTL affecting body conformation and the behavior in dairy cattle. This study provides the first evidence for QTL involved in behavior of dairy cattle and also identifies QTL for udder conformation on chromosome 6 that could form the basis of recently reported QTL for clinical mastitis.

Name of Gene. Inhibin-[Alpha] (INHA). Genus and Species. Capra hircus. Source and Description of Primers. The primers were designed from the flanking sequences of a [(TG).sub.n], microsatellite identified in a 2.2-kb PstI fragment of an ovine cosmid clone, containing the INHA gene (Jager and Hiendleder, 1994). Primer Sequences. Forward Primer: 5'-AGCGTGTGAAGCTGGAGAT-3'; reverse Primer 5'-ACGTGATCACTACCACAGTACGGA-3'. Method of Detection. The PCR (15-[micro]L final volume) was performed using 50 to 100 ng of caprine genomic DNA, 10 pM of each primer, 200 [micro]M of each dNTP, .4 unit of Taq polymerase (AGS, Heidelberg), 1.5 mM [MgCl.sub.2], and PCR buffer (20 mM Tris-HCl, pH 8.55; 1.6 mM [NH.sub.4] [SO.sub.4]). Thermal cycling began with an initial cycle of 94 [degrees] C (1.5 min), followed by 30 cycles of 94 [degrees] C (1 min), 60 [degrees] C (1 min), and 72 [degrees] C (1 min), and concluded with a final extension at 72 [degrees] C (5 min) using a Perkin Elmer Gene Amp PCR system 9600 cycler. For obtaining the allele frequency data, the forward primer was Cy5 fluorescence end-labeled (Amersham-Pharmacia, Freiburg) and the analyses were done using an automated laser detection system (A.L.F. express, Amersham Pharmacia, Freiburg). Amplification of caprine genomic DNA resulted in 210- to 230-bp products that were run on a 5.5% Long Ranger gel (.5 mm, 6 M urea). The genotyping for linkage mapping was done by incorporation of radioactive gamma [P.sup.33] according to Schibler et al. (1998). Description of Polymorphism. The microsatellite containing amplification products showed fragment lengths indicating repeat numbers ranging from [(TG).sub.12] to [(TG).sub.22]. Inheritance Pattern. Codominant inheritance was observed in 12 families. Frequency. The frequencies of alleles in a total of 25 unrelated animals from different breeds (Wei [Beta] e Deutsche Edelziege, Bunte Deutsche Edelziege, Burenziege, Toggenburger Ziege) were .091, .432, .114, .114, .068, .136, and .045 for fragments of 210, 214, 216, 218, 224, 226, and 230 bp. The calculated heterozygosity and PIC (Botstein et al., 1980) in these animals were .75 and .73, respectively. Chromosomal Location. Previous physical mapping by FISH has placed INHA on caprine chromosome 2q41-42 (Goldammer et al., 1995). Linkage Mapping. Significant linkages between the polymorphic INHA-microsatellite and gene markers on chromosome 2 were found using CRI-MAP, version 2.4 (Greene et al., 1989). In the male linkage analysis, the significant two-point LOD scores reported ranged from 3.52 to 7.65 (Table 1). The identified microsatellite was placed in a chromosomal region containing the microsatellite loci ARO 28, BMS 829A, and BMS 829B by multipoint analysis between 110 and 130 cM on chromosome 2, where the microsatellites BMS 829A and BMS 829B were amplified using the same primer pair. Table 1. Results of two-point linkage analyses between the identified microsatellite and genetic markers on goat chromosome 2 Recombination LOD Coinformative Marker fraction score meioses IDVGA37 .18 3.52 67 McM512 .14 6.6 63 BMS829A .10 4.25 41 BMS829B .05 7.65 29 Comments. The PCR product was cloned into the vector pCR 2.1 TOPO (Invitrogen, Leek) and sequenced to confirm homology to the original ovine sequence (GenBank accession no. AF115342) obtained from the ovine cosmid clone. The sequence similarity in microsatellite flanking regions between ovine and caprine loci was 88%. Inhibin is a glycoprotein hormone that suppresses pituitary follicle stimulating hormone secretion (Ling et al., 1985). Two different inhibins have been identified sharing a common [Alpha]-subunit but different [Beta]-subunits ([[Beta].sub.A] and [[Beta].sub.B]). The two forms of inhibin are named with inhibin A ([[Alpha]-[Beta].sub.A]]) and inhibin B ([[Alpha]-[Beta].sub.B]) (Mason et al., 1985). The subunits of inhibin A and B are encoded in three different, independent genes, INHA, INHBA, and INHBB (Findlay et al., 1993). Literature Cited Botstein, D., R. L. White, M. Skolnick, and R. W. Davis. 1980. Construction of a genetic linkage map in man using restriction fragment length polymorphisms. Am. J. Hum. Genet. 32:314-331. Findlay, J. K., S. Xiao, L. Shukovski, and U. Michel. 1993. Novel peptides in ovarian physiology--inhibin, activin and follistatin. In: E. Y. Adashi and P. C. K. Leung (ed.) The Ovary. pp 413-432. Raven Press, New York. Green, P., K. Falls, and S. Crooks. 1989. Documentation for CRIMAP, version 2.4. Washington University, St. Louis, MO. Goldammer, T., R. M. Brunner, S. Hiendleder, and M. Schwerin. 1995. Comparative mapping of sheep inhibin subunits [Alpha] (INHA) and [[Beta].sub.B] (INHBB) to chromosome 2 in goat by FISH. Mamm. Genome 6:685-686. Jager, C., and S. Hiendleder. 1994. Cosmid cloning and characterization of the coding regions and regulatory elements of the ovine [Alpha]- (INHA), [[Alpha].sub.A]-(INHBA) and [[Beta].sub.B]-inhibin (INHBB) genes. Anim. Genet. 25(Suppl. 2):33. Ling, N. 1985. Isolation and patial characterization of a Mr 32000 protein with inhibin activity from porcine follicular fluid. Proc. Natl. Acad. Sci. U.S.A. 82:7217-7221. Mason, A. J., J. S. Hayflick, N. Ling, F. Esch, N. Ueno, S.-Y. Ying, R. Guillemin, H. Niall, and P. H. Seeburg. 1985. Complementary DNA sequences of ovarian follicular fluid inhibin show precursor structure and homology with transforming growth factor-[Beta]. Nature (Lond.) 318:659-663. Schibler, L., D. Vaiman, A. Oustry, C. Giraud-Delville, and E. P. Cribiu. 1998. Comparative gene mapping: a fine-scale survey of chromosome rearrangements between ruminants and humans. Genome Res. 8:901-915. Key Words: Goats, Linkage Groups, Microsatellites

Research was conducted to examine the adrenocorticotropic hormone receptor gene locus. Hybridization experiments were performed on human genomic clones of 1 kb and 2.9 kb to detect polymorphism. A 2-kb rat cDNA was used as a control for the neural melanocortin receptor. Results indicate that adrenocorticotropin induces steroid hormone production in the adrenal gland through specific cell surface receptors.