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Genetic associations of reproductive traits in pigs. In the field of genetics, one of the main research area in relation to animal reproduction is the identification of genes or genomic regions influencing reproductive phenotypes. The genes analysed for the determinants of their fertility are among other: LEP, PRL, PRLR, RBP4. With the use of genetic markers, it is possible to identify of both males and females carrying beneficial alleles, and choose reproduce high-quality individuals, which in turn accelerates the genetic improvement of the examined feature. According to literature, about 30% of culling in pig production systems has been primarily due to reproductive problems. Litter size is very important and easily measured reproductive trait, and often included in scientific researches, and defined as the total number of piglets born (TNB) and the number of piglets born alive (NBA). Selection of individuals carrying favourable alleles has the potential to improve reproductive traits and in this connection also sow productive life (SPL). SLP is a measure of the longevity and reproductive performance of a sow and is directly related to the number of viable piglets produced during its lifespan. Because reproductive traits are so multifaceted, researchers are able to consider many different facets of the organism biology to come up with candidate genes and QTLs genes.
The prolactin receptor gene (PRLR), located on chromosome 16 in pigs, is a candidate gene for reproductive traits. The experiment was aimed to detect the DNA mutations in this gene and to find probable relations between the genotype and some reproductive traits in boars. The polymorphism in the PRLR gene was identified by PCR-RFLP method using specific primers and the restriction enzyme AluI. In total 229 boars of various breeds were genotyped. The frequency of allele A was estimated at 0.62 and allele В at 0.38. Genotype AA was found at a frequency of 0.45, AB at 0.35 and BB at 0.20. We found associations between PRLR genotype and ejaculate volume, sperm concentration, percentage of live sperm, and number of live sperm in the ejaculate (P < 0.01).
Reproduction rate, and litter size in particular, is one of the most economically important aspects of pig production. Progress in researching the porcine genome has enabled polymorphic loci controlling reproduction characteristics in animals to be identified. An example of a gene affecting reproduction is the prolactin receptor (PRLR) gene, which has been mapped to chromosome 16 in pigs. The mechanism through which the PRLR gene affects litter size is not yet known, nor is it known whether the PRLR polymorphism itself causes differences in litter size or whether this polymorphism is a marker for the closely linked major gene for litter size.
The aim of this study was to determine the effect of the calpastatin (CAST) and ryanodine receptor (RYR1) genes polymorphism on carcass and meat quality traits in Pietrain crossbred pigs. No significant differences in the traits examined were identified between pigs with the genotypes CT and CC at the locus RYR1. A significant association occurred between the polymorphisms CAST/PvuII and CAST/RsaI, and the traits characterizing the quality of carcass and composition of meat. Meat from pigs with the genotype AB CAST/PvuII had a significantly higher pH determined 24 and 48 h post mortem, lower drip loss, lower yellowness (b*) and a lower protein content compared to meat from pigs with the genotype AA. In addition, the meat from pigs with the genotype EF CAST/RsaI had a significantly higher pH 48 h post mortem, lower drip loss and lower yellowness (b*) than that of pigs with the genotype EE. The results indicate that several quality and composition traits of fresk meat from the offspring by Pietrain boars are significantly related to the CAST genotype.
The first study of quantitative trait loci (QTL) in pigs showed that genetic factors controlling important economic traits were located on swine chromosome 4. In recent years, the theory that chromosome 4 in pigs contains many QTL loci affecting growth, carcass and meat quality has been confirmed. It would be interesting to show porcine chromosome 4 as a genetic marker for carcass and meat quality traits.
The aim of this study was to evaluate MYH7 single nucleotide polymorphism (SNP) (NC_010449.4: g.7:75667956G>A) in relation to growth and carcass traits in pigs reared in Poland. Previous study has shown that g.7:75667956G>A substitution in pigs influences miR-208b and MYH7 expression, and is associated with proportion of muscle fibre types. The presented study was conducted on 582 pigs belonging to six breeds: Polish Landrace, Polish Large White, Puławska, Pietrain, Duroc and Hampshire. Statistical analysis (GLM procedure) was performed for first three breeds separately and for whole group together. Our study showed that investigated SNP was associated with test daily gain, average daily gain, age at slaughter and number of days in experiment (P ≤ 0.05 or P ≤ 0.01) in Polish Large White, Puławska and whole group. Among carcass traits MYH7 variants influenced mean backfat thickness from 5 measurements (P ≤ 0.05) in the same groups. We also noticed some associations for slaughter efficiency, weight of loin without backfat and skin, loin eye area and meat percentage (P ≤ 0.05 or P ≤ 0.01) but results were not consistent among breeds and whole group. Obtained results indicate that MYH7 SNP could be used as a genetic marker for improvement of some growth traits and backfat thickness in pigs
The synthesis of estrogens from androgens is catalyzed by an enzyme complex called aromatase, and therefore has a unique potential to influence the physiological balance between the sex steroid hormones. This enzyme complex consists of two components: aromatase cytochrome P450 and NADPH-cytochrome P450 reductase. Aromatase is conserved amongst all vertebrates and mammals in particular. It is a member of the cytochrome P450 super-family of enzymes. Within this, aromatase cytochrome P450 is presently the sole member of family 19, and is encoded by the gene known as CYP19 which contains a number of tissue-specific promoters that direct aromatase expression in different tissues via alternative splicing. A number of tissues in mammals have the capacity to express aromatase. These include the ovaries and testes, the placenta, adipose tissue, osteoblasts of bone, vasculature smooth muscle, and numerous sites in the brain.
The aim of this study was to detect SNPs in exon 10 of the chinchilla growth hormone receptor gene (GHR) by comparative sequencing. Sixty females of the same breed (Standard) were analysed. Four new SNPs were identified, which cause 3 amino acid substitutions in the intracellular domain of the receptor: G/C at position 135 bp (in relation to the total sequence of exon 10) (gln/his), CAG/AAA at 352 bp and 354 bp (gln/lys), and C/A at 641 bp (thr/asn).
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