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Biomedical subjects

S M Schmutz

Publications and source records attributed to S M Schmutz.

At least 19 recordsLinked to original sources
PubMed1999

Transmitochondrial differences and varying levels of heteroplasmy in nuclear transfer cloned cattle.

To assess the extent of cytoplasmic genetic variability in cloned cattle produced by nuclear transplantation procedures, we investigated 29 individuals of seven male cattle clones (sizes 2-6) from two different commercial sources. Restriction enzyme and direct sequence analysis of mitochondrial DNA (mtDNA) detected a total of 12 different haplotypes. Transmitochondrial individuals (i.e., animals which share identical nuclei but have different mitochondrial DNA) were detected in all but one of the clones, demonstrating that mtDNA variation among cloned cattle is a very common phenomenon which prevents true genetic identity. The analyses also showed that the cytoplasmic genetic status of some investigated individuals and clones is further complicated by heteroplasmy (more than one mtDNA type in an individual). The relative proportions of different mtDNA-types in two animals with mild heteroplasmy were estimated at 2:98% and 4:96% in DNA samples derived from blood. This is in agreement with values expected from karyoplast-cytoplast volume ratios. In contrast, the mtDNA haplotype proportions observed in six other heteroplasmic animals of two different clones ranged from 21:79% to 57:43%, reflecting a marked increase in donor blastomere mtDNA contributions. These results suggest that mtDNA type of donor embryos and recipient oocytes used in nuclear transfer cattle cloning should be controlled to obtain true clones with identical nuclear and cytoplasmic genomes.

Animals↗
PubMed1999

A missense mutation in the bovine MGF gene is associated with the roan phenotype in Belgian Blue and Shorthorn cattle.

The Roan locus is responsible for the coat coloration of Belgian Blue and Shorthorn cattle. The solid-colored and white animals are homozygotes, and the roan animals, with intermingled colored and white hairs, are heterozygous. The roan phenotype was mapped to cattle Chromosome (Chr) 5 with microsatellites, and a candidate gene was proposed (Charlier et al. Mamm Genome 7, 138, 1996). PCR primers to the exons of this candidate gene, the steel locus or mast cell growth factor (MGF) were designed. Solid-colored and white animals were sequenced. A missense mutation at 654 bp (amino acid 193, Ala --> Asp) was detected in these two groups. A PCR-RFLP was designed to this single base pair change, and 143 animals in total (Belgian Blue, Shorthorn, and various other breeds) were screened. In addition, the Canadian Beef Cattle Reference Herd (http://skyway. usask.ca/ approximately schmutz) was used to verify Mendelian inheritance of this marker with the phenotypic inheritance of roan. Our data suggest that this mutation in the bovine MGF gene is responsible for the roan phenotype.

Animals↗
PubMed1998

A potential association between the BM 1500 microsatellite and fat deposition in beef cattle.

The obese gene was hypothesized as a candidate gene for fat characteristics in beef cattle. The BM 1500 microsatellite, near the obese gene, was characterized in 158 purebred beef bulls for which carcass trait information was available. Four breeds were included in the analyses-Angus, Charolais, Hereford, and Simmental. Four alleles were found. Lengths were approximately 138, 147, 149, and 140 bp with genotypic frequencies of 0.47, 0.44, 0.09, and 0.003 respectively. The carcass traits %rib fat, %rib lean, average fat, and grade fat were found to be significantly associated with the different alleles. The presence of the 138-bp allele in the genotype of an animal is correlated with higher levels of fat, whereas the 147-bp allele has the opposite effect. The 149-bp allele was found in low numbers, and a homozygote was never identified. Hereford and Angus bulls had the greatest frequencies of 138-bp alleles (Hereford = 0.57, Angus = 0.59), while Charolais and Simmental had a greater proportion of 147-bp alleles (Charolais = 0.54, Simmental = 0.58). This information may aid cattle producers in selecting cattle for markets that differ in the amount of fat required.

Adipose Tissue↗
PubMed1998

In situ hybridization of five loci to cattle chromosome 1.

The genes for pituitary-specific transcription factor (PIT1), propionyl coenzyme A carboxylase, beta-polypeptide (PCCB), transferrin (TF), trichohyalin (THH), and involucrin (IVL) were mapped to cattle chromosome 1 (BTA 1) by isotopic in situ hybridization. Two of the loci were mapped from cattle PCR products and three from human ATCC probes. PIT1 localized to segment 1q2; PCCB to 1q3; and TF, THH, and IVL to 1q4. These localizations agree with the homology previously shown between BTA 1 and human chromosome 3 (HSA 3). Some homology with HSA 1 has been established with the mapping of THH and IVL to BTA 1q4.

Animals↗
PubMed1998

Black hair follicular dysplasia, an autosomal recessive condition in dogs.

Using histology, a coat color abnormality and the subsequent hair loss were diagnosed as black hair follicular dysplasia. A pedigree analysis of an affected litter and literature review suggests that this is inherited as an autosomal recessive trait. The melanocyte stimulating hormone receptor gene is ruled out by using linkage analysis.

Animals↗
PubMed1996

Physical mapping of SOD1 to bovine chromosome 1.

Superoxide dismutase 1 (SOD1) was mapped to cattle chromosome 1q12 --> q14 by in situ methods. Both traditional in situ hybridization using tritium and a new technique, direct in-situ single copy PCR (DISC-PCR), were used in two separate laboratories. Both human and bovine SOD1 clones were tritium labeled for radioactive in situ hybridization. A primer pair based on the bovine SOD1 gene (Barendse et al., 1994b) was used for the DISC-PCR procedure. The map location of SOD1 is close to collagen 6A1. SOD1 is a potentially important type 1 anchor locus in the region where the gene for horns in cattle was recently mapped (Georges et al., 1993; Schmutz et al., 1995).

Animals↗
PubMed1996

Chromosomal aneuploidy associated with spontaneous abortions and neonatal losses in cattle.

Pericardial sac samples from 77 bovine aborted fetuses and stillborn calves were submitted for tissue culture; cells from 55 of these samples were grown successfully in culture. Six of the 55 karyotyped fetuses (10.7%) had an abnormal chromosome complement, in 3 of which (5.5%) the abnormality was probably the cause of death. This level of abnormality is relatively high when one considers that most fetuses were >8 months gestational age. Approximately 5-7% of human stillbirths and 50% of first-trimester aborted fetuses have chromosome anomalies. If a similar situation exists in cattle, as suggested by these data, chromosome abnormalities may be a major cause of early fetal loss in cattle. Most chromosomally abnormal fetuses had multiple malformations, which suggests that the diagnostic use of chromosome analysis is most cost effective for malformed fetuses and newborns. Twins were present in a higher proportion of these fetuses than expected based on their incidence among liveborn cattle.

Abortion, Veterinary↗
PubMed1995

DNA marker-assisted selection of the polled condition in Charolais cattle.

Five Charolais families known to segregate for both horned and polled were selected and tested for linkage analysis by use of microsatellites and karyotyping for Robertsonian translocation 1;29. No recombinants were found between any of these markers and the polled phenotype or each other. When statistical analysis was performed, the logarithm of the odds (LOD) indicated that there was 100% linkage occurring between the markers and the phenotype (p < 0.001). These microsatellite markers, TGLA49 and BM6438, can be assumed to be very close to the actual gene that determines the polled phenotype. Another linked marker, SOD1, was physically mapped, which places all of these markers within 1q12-14, very near the centromere of Chromosome (Chr) 1. A homozygous polled cow was identified in this study by following the alleles at both markers and the phenotypes in her family.

Animals↗
PubMed1994

Gene mapping from a bovine 1;29 DNA library prepared with chromosome microdissection.

Bovine gene mapping is progressing rapidly using syntenic group mapping based on somatic cell hybrids and linkage, and to a lesser extent on in situ hybridization. Single chromosome DNA libraries are a logical next step, and this was, therefore, the aim of our laboratory. Since we have access to several cattle with t(1;29) and this chromosome is readily distinguishable, we chose this as our first target--recognizing that we would not produce a "single" chromosome library in the strict sense because two autosomes are represented. We utilized an inverted microscope and a micromanipulator fitted with glass instruments pulled specifically to dissect off approximately 100 t(1;29) chromosomes per microdrop. A glass chamber made to accommodate a hanging drop was used to extract the DNA under a dissecting microscope. The DNA was then cleaved with EcoRI and inserted in lambda gtwes arms. Host cells were then infected with these phage and positive clones obtained. The first clone, isolated from this library by hybridization with a human collagen 6A1 cDNA, was mapped by in situ hybridization to bovine Chromosome some (Chr) 1q12-q14, near the centromere. The second clone, an anonymous DNA fragment (D1S11), was mapped to 1q43-q46, near the terminal end.

Animals↗
PubMed1992

Detection of leucochimaerism in bovine twins by DNA fingerprinting.

Karyotyping and hypervariable genetic markers indicate extensive leucochimaerism between pairs of dizygotic twins in cattle, a result of placental vascular anastomosis. The extent of this chimaerism includes both kind and number of cells exchanged. All heterosexual twin pairs harboured two types of leucocytes, having either XX or XY chromosome pairs, and 30 of 31 pairs of twins shared identical DNA fingerprints. Although chromosome results from skin fibroblasts indicate that some chimaerism occurs in the skin, the low level allows for differentiation of genotypes between twins. The results warrant against the common practice of using blood samples for DNA typing if twinning is not properly documented.

Animals↗