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ARS Home » Plains Area » Houston, Texas » Children's Nutrition Research Center » Research » Publications at this Location » Publication #76372
Title: DISTRIBUTION OF ALLELES OF THE CHOLESTEROL 7 ALPHA-HYDROXYLASE (CYP7) GENE IN PIGS SELECTED FOR HIGH OR LOW PLASMA TOTAL CHOLESTEROL

Author
item DAVIS, ANGELA - MCLAUGHLIN RES INST.
item WHEELER, MATTHEW - UNIVERSITY OF ILLINOIS
item Mersmann, Harry
item Ishimura-Oka, Kazumi
item SU, DAI-RONG - BAYLOR COLL OF MEDICINE
item LI, CHEE - BAYLOR COLL OF MEDICINE

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/29/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Scientists are interested in controlling the amount of blood cholesterol for many reasons. In humans, it is optimal to avoid high blood cholesterol to avoid heart disease from clogged arteries. Scientists have developed a strain of pigs selected for high or low total cholesterol to study interactions with nutrition and other factors and traits. There is a tendency for pigs with low cholesterol to be fatter and have less lean meat. In this study, we identified a genetic marker that can be detected at a piglet's birth, which could act as a valuable selection tool to predict a desired trait when the pig grows up and is ready to go to market. We used a specific technique, called restriction fragment length polymorphism analysis with TaqI of the CYP7 gene a good marker for determining total blood cholesterol in swine. What that means is that we found a good tool to identify a gene that will help select infant pigs that will grow up to have ethe kinds of body traits, based on total cholesterol, that are desired for market value, such as carcass leanness and body weight at slaughter.

Technical Abstract: Crossbred pigs (Chester White x Landrace x Large White x Yorkshire) have been selected for high (HTC) or low (LTC) plasma total cholesterol (TC). Pigs from the seventh (n=51) and eighth (n=139) generations were used to determine restriction fragment length polymorphisms (RFLP). Using TaqI restriction enzyme digestion, the frequency of one or the other of two alleles (2.8 or 5.0 kb fragments) of the cholesterol 7 alpha-hydroxylase (CYP7) gene was 8 wk of age. Only the 2.8 kb fragment allele was present in the 26 HTC pigs tested in generation 7, whereas both the 2.8 and 5.0 kb alleles were present in 12 and only the 5.0 kb allele was present in 13 of the LTC pigs. The allele frequencies of the 2.8 and 5.0 fragments, respectively, were 26% and 74% in LTC pigs and 100 and 0% in HTC pigs. There was an association (P<.001) between the 5.0 and 2.8 kb CYP7 alleles, respectively, and low and high TC concentrations. In generation 8, all HTC pigs were homozygous for the 2.8 kb allele except for all 10 pigs in one litter whose sire was phenotypically HTC but found to be homozygous for the 5.0 kb allele of the CYP7 gene. The 5.0 kb allele was present in all LTC pigs tested and was homozygous in 55% of LTC pigs. Mean plasma TC was 105.0 mg/dL in 30 pigs homozygous for the 2.8 kb allele in generation 8; means for LTC pigs were 53.5 and 60.4 mg/dL in 35 pigs homozygous for the 5.0 kb allele and in 26 heterozygous pigs, respectively. High TC was associated with the presence of the 2.8 kb allele and low TC as associated with the presence of the 5.0 kb allele in both generations 7 and 8. We conclude that TaqI RFLP analysis of the CYP7 gene is a reliable marker for TC and correlated traits in swine.