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ABSTRACT
A genetic linkage map for the duck (Anas platyrhynchos) was developed within a cross between two extreme Peking duck lines by linkage analysis of 155 polymorphic microsatellite markers, including 84 novel markers reported in this study. A total of 115 microsatellite markers were placed into 19 linkage groups. The sexaveraged map spans 1353.3 cM, with an average interval distance of 15.04 cM. The male map covers 1415 cM, whereas the female map covers only 1387.6 cM. All of the flanking sequences of the 155 polymorphic loci-44 monomorphic loci and a further 41 reported microsatellite loci for duck-were blasted against the chicken genomic sequence, and corresponding orthologs were found for 49. To integrate the genetic and cytogenetic map of the duck genome, 28 BAC clones were screened from a chicken BAC library using the specific PCR primers and localized to duck chromosomes by FISH, respectively. Of 28 BAC clones, 24 were detected definitely on duck chromosomes. Thus, 11 of 19 linkage groups were localized to 10 duck chromosomes. This genetic and cytogenetic map will be helpful for the mapping QTL in duck for breeding applications and for conducting genomic comparisons between chicken and duck.
MOLECULAR genetic maps will provide insight into the genome organization and chromosomal localization of cloned genes and also a framework for the identification and localization of major genes associated with economically important traits (CRITTENDEN et al. 1993). The rapid progress being made in the development of genetic maps for humans and mice has led to a recent boom in the construction of genome maps for many farm animals. High-density linkage maps are now available for many species, such as pigs, cattle, sheep, and goats. In contrast, mapping studies in avian species are much less advanced except in the chicken. To construct saturated genetic maps for more bird species, the isolation of many polymorphic genetic markers, particularly microsatellite markers, is a prerequisite. Although many chicken markers were available, it was difficult to screen the microsatellite marker for the duck by cross-species amplification from this species because of the poor conservation of the microsatellite sequences between the species (HUANG et al. 2005).
Microsatellites or simple sequence repeats are tandem repeated motifs of 1-6 bases found in all prokaryotic and eukaryotic genomes and...