RADIATION HYBRID AND GENETIC LINKAGE MAPPING OF TWO GENES RELATED TO FAT METABOLISM IN CATTLE: FATTY ACID SYNTHASE (FASN) AND GLYCEROL-3-PHOSPHATE ACYLTRANSFERASE MITOCHONDRIAL (GPAM)

ABSTRACT

Fatness traits, such as fat deposition, carcass composition, fat content, and the percentage of fat in milk, are economically relevant to cattle production. Fatty acid synthase (FASN) and glycerol-3-phosphate acyltransferase mitochondrial (GPAM) are two enzymes that play a central role in de novo lipogenesis. Both could be putative candidate genes for quantitative trait loci (QTL). Several clones containing the fatty acid synthase (FASN) and glycerol-3-phosphate acyltransferase mitochondrial (GPAM) genes were isolated after screening the INRA bovine bacterial artificial chromosome (BAC) library using PCR. Five microsatellite loci were derived from the BAC clones containing the genes of interest with heterozygosity values ranging from 27 to 78%, using DNA samples from the International Bovine Reference Panel (IBRP). The newly developed markers were genotyped on the IBRP animals and on a radiation hybrid panel to compare the obtained linkage and RH maps. Radiation hybrid maps were developed for chromosome BTA19 and BTA26 regions containing FASN and GPAM genes, respectively. The two genes and their associated microsatellite markers were located on the genetic or RH maps or on both. These microsatellite markers could be useful to study the QTL effect on fat synthesis in reference population.

Keywords:

• Candidate gene
• Fat metabolism
• BTA26
• BTA19
• Genetic and physical mapping

ACKNOWLEDGMENTS

The authors wish to thank W. Barendse (editor of Cattle Genotypic Database) for performing the linkage analysis. This work was supported by a grant from the Spanish Ministry of Education and Science (MEC).

Notes

^a Microsatellite sequences can be accessed in GenBank (accession numbers).

^b T_a. Annealing temperature used to generate genotypes via PCR amplification.

^c Marker heterozygosity observed in IBRP families (n = 38).

^d Data only shown for large LOD scores from two-point linkage analysis with Cri-map.

^e Marker identified to have the largest LOD score with marker in locus column.