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Biomedical subjects

G A Rohrer

Publications and source records attributed to G A Rohrer.

At least 19 recordsLinked to original sources
PubMed2000

Biochemical and genetic characterization of the porcine Prophet of Pit-1 pituitary transcription factor.

Prophet of Pit-1 (Prop-1) is a paired class homeodomain transcription factor that is specifically expressed in the pituitary gland. Mutations in the Prop-1 gene cause compound pituitary diseases in mouse models and human patients. We have cloned and analyzed the porcine ortholog of Prop-1. Analysis of cDNAs revealed that the porcine Prop-1 sequence is similar to the mouse and human proteins within the homeodomain and carboxyl terminus, but the amino terminus is poorly conserved. The Prop-1 gene consists of three exons and two introns and spans 3.8 kilobases of genomic DNA. In addition, we mapped Prop-1 to the q arm of pig chromosome two. During development, Prop-1 is expressed at the time of pituitary organogenesis. In the adult, expression was observed at low levels only in the pituitary gland. The porcine Prop-1 protein displays similar biochemical, DNA binding, and transcriptional activities to human PROP-1. We conclude that, although the structural divergence between the porcine and human PROP-1 molecules may indicate some distinct functions, the porcine Prop-1 gene encodes a pituitary transcription factor with similar overall activities to the human ortholog.

Amino Acid Sequence↗
PubMed2000

Identification and characterization of a new allele for the beta subunit of follicle-stimulating hormone in Chinese pig breeds.

During evaluation of follicle-stimulating hormone-beta (FSHB) expression in anterior pituitary glands by an RNase protection assay (RPA), the expected fragment of 205 nucleotides at positions 759-963 was not detected in one boar that had moderate plasma and pituitary FSH concentrations. After subcloning and sequencing, mRNA from this boar lacked an 11-bp fragment (5'-CATTTGGAAAC-3') at nucleotide positions 807-817 of the 3'-untranslated region (3'-UTR, D allele). Wild-type FSHB (WT allele) was present in pituitary RNA and genomic DNA in both Meishan (MS) and White Composite (WC) pigs; whereas the D allele was present only in MS pigs (P < 0.01; 5/6 MS vs. 0/6 WC). Also, we found the D allele in five other Chinese breeds but absent in ten American Landrace, 11 Yorkshire and 17 Berkshire pigs. Additionally, the D allele had one silent nucleotide change in the coding region plus six, single nucleotide changes in the 3'-UTR.

3' Untranslated Regions↗
PubMed2000

Identification of quantitative trait loci affecting birth characters and accumulation of backfat and weight in a Meishan-White Composite resource population.

A search for genomic regions affecting birth characters and accretion of weight and backfat was conducted in a Meishan-White Composite reciprocal backcross resource population. Birth traits analyzed (n = 750) were vigor score, number of nipples, and birth weight. Subsequent measures on gilts and barrows (n = 706) analyzed were weaning weight, 8-wk weight, ADG from 8 to 18 wk of age, ADG from 18 to 26 wk of age, 26-wk weight, and backfat over the first rib, last rib, and last lumbar vertebrae at 14 and 26 (n = 599) wk of age. Feed intake and growth of 92 individually penned barrows were also analyzed. A genomic scan was conducted with microsatellite markers spaced at approximately 20-cM intervals, a least squares regression interval analysis was implemented, and significance values were converted to genomewide levels. No associations were detected for traits measured at birth except for number of nipples, where one significant and two suggestive regions were identified on chromosomes (SSC) 10, 1, and 3, respectively. Early growth was affected by a region on SSC 1 as evidenced by associations with weights collected at weaning and 8 wk of age and ADG from 8 to 18 wk of age. Other regions detected for early growth rate were on SSC 2, 12, and X. Chromosomal regions on SSC 6 and 7 affected ADG from 18 to 26 wk of age. All measures of backfat were affected by regions on SSC 1 and X, whereas SSC 7 consistently affected backfat measures recorded at 26 wk of age. Suggestive evidence for QTL affecting backfat at 14 wk of age was also detected on SSC 2, 6, 8, and 9. These results have improved our knowledge about the genetics of growth rate and fat accretion at the molecular level in swine.

Adipose Tissue↗
PubMed1999

Interval mapping of growth in divergent swine cross.

A genomic scan of 18 swine autosomal chromosomes was constructed with 119 polymorphic microsatellite (ms) markers to identify quantitative trait loci (QTL) for 11 growth traits in the University of Illinois Meishan x Yorkshire Swine Resource Family. A significant QTL effect was found for post-weaning average daily gain (ADG) between 5.5 and 56 kg of body weight that mapped between markers SW373 and SW1301 near the telomere of Chromosome (Chr) 1 q (SSC1). This QTL effect had a nominal (pointwise) p-value of 0.000007, a genome wide p-value of 0.012, and accounted for 26% of the F2 phenotypic variance. The same chromosome region also had significant effects on ADG between birth and 56 kg body weight (p-value =. 000227), and on ADG between 35 and 56 kg (p-value =.00077). These observations suggest that a significant QTL for post-weaning growth resides on SSC1.

Animals↗
PubMed1999

Mapping four genes from human chromosome 4 to porcine chromosome 8 further develops the comparative map for an economically important chromosome of the swine genome.

Because porcine chromosome (SSC) 8 has become the focal point of many efforts aimed at identifying quantitative trait loci affecting ovulation rate, genes distributed across human chromosome (HSA) 4 were physically mapped in the pig. A more refined comparative map of this region for these two species was produced. In this study, four genes were selected based on their location in the human genome, the availability of nucleotide sequence and their genomic organization. The genes selected were fibroblast growth factor basic (FGF2; HSA 4q25-27), gonadotropin releasing hormone receptor (GNRHR; HSA 4q13), phosphodiesterase 6 B (PDE6B; HSA 4p16.3) and aminopeptidase S (PEPS; HSA 4p11-q12). Genomic libraries were screened via PCR and clones were physically assigned using fluorescence in situ hybridization (FISH). These four genes from HSA 4 were physically mapped to SSC 8p2.3 (PDE6B), 8p1.1 (PEPS), 8q1.1-1.2 (GNRHR) and 8q2.2-2.4 (FGF2). These assignments provide additional benchmarks for the comparative map and help define the level of gene order conserved between HSA 4 and SSC 8.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1999

Cytogenetic assignment of 53 microsatellites from the USDA-MARC porcine genetic map.

This study provides 53 new fluorescent in situ hybridization cytogenetic assignments for microsatellite markers linked on the swine genetic map. Forty microsatellites are physically assigned for the first time. The chromosomal locations of eight markers were either confirmed or refined, while five loci were assigned to locations different from those given in previous reports. Markers were selected to provide physical anchors based on their presumed proximity to centromeres or telomeres and at approximately 30 cM intervals across the genetic map. The number of physical anchors for pig (SSC) chromosomes 8, 15, and 18 linkage groups was significantly improved. Centromeric regions were localized to areas less than 10 cM for SSC 1, 2, 3, 6, 7, 8, and 9. Although the recombination rate was generally higher across small biarmed chromosomes and lowest for large acrocentric chromosomes, two regions with particularly low (1q2.1-->q2.9 and 13q2.3-->q4.1) and three regions with extremely high (5p1.5-->p1.2, 6p1.4-->p1.3, and 12p1.5-->p1.4) rates of recombination were detected. These assignments represent an overall 10% increase in the number of physically assigned markers in Sus scrofa and more than a 20% increase in the number of Type II loci assigned to the pig cytogenetic map.

Animals↗
PubMed1999

Identification of quantitative trait loci affecting female reproductive traits in a multigeneration Meishan-White composite swine population.

A multigeneration crossbred Meishan-White composite resource population was used to identify quantitative trait loci (QTL) for age at first estrus (AP) and the components of litter size: ovulation rate (OR; number of ova released in an estrous period) and uterine capacity (UC). The population was established by reciprocally mating Meishan (ME) and White composite (WC) pigs. Resultant F1 females were mated to either ME or WC boars to produce backcross progeny (BC) of either 3/4 WC 1/4 ME or 1/4 WC 3/4 ME. To produce the next generation (F3), 3/4 WC 1/4 ME animals were mated to 1/4 WC 3/4 ME animals yielding half-blood (1/2 WC 1/2 ME) progeny. A final generation (F4) was produced by inter se mating F3 animals. Measurements for AP and OR were recorded on 101 BC, 389 F3, and 110 F4 gilts, and UC data were from 101 BC and 110 F4 first parity litters. A genomic scan was conducted with markers (n = 157) spaced approximately 20 cM apart. All parental, F1, BC, and F4 animals but only 84 F3 animals were genotyped and included in this study. The QTL analysis fitted a QTL at 1-cM intervals throughout the genome, and QTL effects were tested using approximate genome-wide significance levels. For OR, a significant (E[false positive] < .05) QTL was detected on chromosome 8, suggestive (E[false positive] < 1.0) QTL were detected on chromosomes 3 and 10, and two additional regions were detected that may possess a QTL (E[false positive] < 2.0) on chromosomes 9 and 15. Two regions possessed suggestive evidence for QTL affecting AP on chromosomes 1 and 10, and one suggestive region on chromosome 8 was identified for UC. Further analyses of other populations of swine are necessary to determine the extent of allelic variation at the identified QTL.

Animals↗
PubMed1998

Evaluating evolutionary divergence with microsatellites.

We report the use of microsatellites (MS) to track the recent evolution of swine. Allelic frequencies for nine MS loci linked on swine chromosome 6 (SSC6) representing four western and one Chinese swine breeds were used to estimate genetic distances and times of breed divergence. A phylogenetic tree was constructed which partitioned into western and Meishan breed branches. Yorkshire and Hampshire breeds exhibited the most recent divergence with a calculated distance of 391 years. The oldest divergence, of 2,227 years, was between Meishan and Hampshire swine. Estimates of breed divergence are consistent with historical records. Additional analysis suggests that polymorphic MS linked on a single chromosome are sufficient to determine evolutionary relationships within a single species.

Animals↗