Effects of quantitative trait loci on chromosomes 1, 2, 4, and 7 on growth, carcass, and meat quality traits in backcross Meishan × Large White pigs1

Abstract

The aim of this work was to estimate whether genetic dissection of QTL on chromosomes 1, 2, 4, and 7, detected in an F2 Meishan x Large White population, can be achieved with a recombinant back-cross progeny test approach. For this purpose, a first generation of backcross (BC1) was produced by using frozen semen of F1 Large White x Meishan boars with Large White females. Four BC1 boars were selected because of their heterozygosity for at least 1 of the 4 regions. The BC1 boars were crossed with Large White sows, and the resulting BC2 offspring were measured for several growth and body composition traits. Contrary to the F2 animals, BC2 animals were also measured for meat quality traits in adductor, gluteus superficialis (GS), longissimus dorsi, and biceps femoris (BF) muscles. Each BC1 boar was tested for a total of 39 traits and for the 4 regions with statistical interval mapping analyses. The QTL effects obtained in BC1 families showed some differences compared with those described in F1 families. However, we confirmed QTL effects for growth in the SW1301-SW2512 markers interval on chromosome 1 and also for body composition in the SW1828-SW2512 markers interval on chromosome 1, in the SW2443-SWR783 markers interval on chromosome 2, and in the SW1369-SW632 markers interval on chromosome 7. In addition, we detected new QTL for growth traits on chromosome 2 and for meat quality traits on chromosomes 1 and 2. Growth of animals from weaning to the end of the test was influenced by the IGF2 gene region on chromosome 2. Concerning meat quality, ultimate pH of adductor, longissimus dorsi, and BF were affected by the interval delimited by UMNP3000 and SW2512 markers on chromosome 1, and a* of GS, L* of BF, and water-holding capacity of GS were affected by QTL located between marker loci SW2443 and SWR783 on chromosome 2. Recombinant progeny testing appeared to be a suitable strategy for the genetic dissection of the QTL investigated.

QTL analysis for carcass composition and meat quality traits on SSC7q1.1-q1.4 region in Large White × Meishan F₂ pigs

“…The additive effect of the QTL was 0.21 cm, with the Large White allele increasing the LEW. Although several studies reported that there were significant QTL affecting LP and LEA around this region using different experimental animals (Sato et al, 2003;Yue et al, 2003;Sanchez et al, 2006;Uemoto et al, 2008), no QTL for LP and LEA with significant level were detected in the present study. This phenomenon might be due to the differences of experimental designs as well as statistical models.…”

Detecção de locos de características quantitativas nos cromossomos 1, 2, 3, 12, 14, 15 e X de suínos: características de desempenho

“…Assim como no presente trabalho, Sanchez et al (2006) encontraram QTL para GPD na posição distal do SSC1 (87cM) ao estudarem uma população Meishan x Large White. Beeckmann et al (2003) encontraram QTL para CR a 117,2cM e 74,3cM e para GPD a 59,7cM, no SSC1 de suínos selvagens europeus x Pietrain.…”

Genome-wide identification of QTL for age at puberty in gilts using a large intercross F2 population between White Duroc × Erhualian

“…At the QTL for age at puberty on SSC7, one interesting phenomenon is that the favourable QTL allele originates from the Duroc breed, which is in contradiction with the breed characteristic differences for this trait. This observation has been repeatedly documented in many QTL studies around this region, such as the QTL for fat androstenone levels [21] and for QTL for age at puberty in gilts average daily gain [26]. The reason for this remains unknown.…”

“…The two QTL regions on SSC7 and SSC1 are of particular interest, showing highly significant associations across different resource populations. Future work will be directed at fine mapping of the QTL identified using additional markers and advanced intercross populations or recombination backcross populations [26].…”