Family and/or Friends? Gene Mapping at Crossroads

Mapping gene(s) underlying a specific trait offers an opportunity to plant breeders to apply marker assisted selection. All gene mapping approaches except LD mapping use family based segregation populations developed by crossing two or more parents. These family based gene mapping approaches include simple interval mapping, composite interval mapping, multiple interval mapping and Bayesian mapping etc. Each approach has its own advantages and disadvantages based on type of population and underlying statistical model. Unlike family based approaches, LD mapping uses population of unrelated individuals which are like friends belonging to different family backgrounds. Relative pros and cons of family and friends based approaches make them complementary to each other. Family based approaches identify wide chromosomal region underlying the trait of interest with relatively lower markers density, and therefore, have low mapping resolution. Conversely, friends based LD mapping identifies chromosomal region of interest with higher resolution using higher marker density. The integration of family and friends based approaches addresses their respective pros and cons successfully to enhance mapping resolution for more valid application of marker assisted selection.