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Inbreeding, alleles fixation and selection limit in populations under traditional or marker assisted selection methods

This study aimed to evaluate the inbreeding coefficient, alleles fixation and selection limit in a population selected during 20 generations. Selection was based on breeding values predicted by classical best linear unbiased prediction (BLUP), BLUP associated with molecular markers (BLUPM) and individual selection (IS) using different mating designs. The genetic similarity matrix used in BLUPM was obtained by simulating 100 micro satellite markers (simple sequence repeats) using a similarity coefficient corresponding to the mean Euclidean distance between quantitative data. The selection methods were compared using populations with an effective size of 66.66 and a mean of 30 repetitions. The largest increase in inbreeding was observed for BLUPM, followed by BLUP and SI. The methods based on BLUP provided the higher fixation of favorable and unfavorable alleles. The BLUPM method provided the higher reduction in the selection limit during the twenty generations. Systems excluding between sibs mating resulted in lower increases in inbreeding rates, fewer losses due to unfavorable allele fixation and smaller decreases in selection limit.

BLUP; mating systems; selection; simulation


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