Nevertheless, these isogenic individuals are not completely identical, but show phenotypic discordance for many traits from birth weight to a range of complex diseases [ 24].
The parental genotypes in this study varied considerably in many traits relevant for N economy under drought, indicating a potential for plant breeding when crossed.
It shows many traits typical for wild plants, such as secondary seed dormancy, adaptation of its seed germination to the annual cycle and the easy dehiscence of its fruits.
For many traits, and more specifically for those under lower selection pressure, genetic variability must still be high within and across chicken populations.
The 15.82 Mb region of BTA18 with approximately 1,322 genes had SNP effects for many traits but was most pronounced for service-sire and daughter calving ease and service-sire stillbirth.
Quantitative trait loci (QTLs) for many traits in chicken have been studied for over 20 years; 52 QTLs for meat-quality traits and 272 for abdominal fat traits have been detected in a variety of chicken chromosomal regions [ 4].
Although QTL have already been reported in chicken for many traits, there are very few QTL reported for meat characteristics [ 8]T.
For many traits, phenotypic selection is costly and time consuming, especially so for traits expressed late in the life cycle of long-lived species.
