Abstract

Marbling and intramuscular fat (IMF) content are commonly used to describe or measure intramuscular fat deposition in meat, which contributes to taste, texture and flavor. Four types of genetic markers, i.e., microsatellite, random amplification of polymorphic DNA (RAPD), amplified fragment length polymorphisms (AFLP) and single nucleotide polymorphisms (SNPs) have been used in genome scans or association studies to detect quantitative trait loci (QTL) for these traits in cattle and swine. For the most part microsatellite markers help define QTL regions but have been used in limited ways to patent gene tests because of the uncertainties associated with the microsatellite marker scans. However, SNPs in candidate genes selected based on physiological, positional or comparative information often lead to patent applications once strong associations have been determined. To date, at least 22 patents have been awarded or under review for genes/markers affecting marbling or IMF in cattle and swine. Unfortunately, similar muscle lipid accumulation in humans has significant negative impacts on health, causing obesity/type 2 diabetes and their associated conditions. Many studies have also been performed on human subjects or on the mouse as a model organism to understand the genetic complexity of these conditions. A collection of over 2,000 reports on genes/markers affecting fat phenotypes in humans, mice, cattle and swine have led to construction of a mammalian concordant QTL map for lipogenesis. The concordant QTL map provides power for fine mapping and narrowing each of these QTL regions to a few genes.

Keywords: Muscle lipid accumulation, gene tests, patents, meat quality, human health