|PONCE DE LEON, ABEL|
Submitted to: Cytogenetics and Cell Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/15/1997
Publication Date: N/A
Interpretive Summary: Improvement of carcass quality in swine has seen major advances in the last few decades due to improved breeding stock. The advent of genomic studies has opened up the possibility of using radically new methods to verify inheritance of desired characteristics by using quick DNA analyses rather than extended growth studies. In swine, genes on chromosome 6 have long been known to be important in defining desirable carcass traits. This manuscript reports the results of a multisite collaboration to develop new DNA markers only on swine chromosome 6. Swine genomic DNA libraries were produced by scraping just 10 copies of swine chromosome 6, thus ensuring high purity of input DNA. DNA markers, termed microsatellites, were then cloned from this library, sequenced, and shown to map on swine chromosome 6. A total of 9 markers were defined and placed on the swine chromosome 6 linkage map. Now studies can verify whether unique genetic alleles at these markers are associated with improved carcass traits. If such a correlation is proven, then future breeding stock could be characterized for this DNA marker, not by the extensive growth tests. This DNA testing would make it much faster and easier to identify the highest quality swine breeding stock.
Technical Abstract: To facilitate the identification of microsatellite genetic markers from a single swine chromosome, chromosome microisolation and microcloning has been used to generate a swine chromosome 6-specific DNA library. Ten copies of swine chromosome 6 were scraped from metaphase spreads, ligated to custom-prepared adaptors and amplified by PCR. The purity of the amplified product was verified by fluorescent in situ hybridization (FISH) Further, the utility of the chromosome painting probe for heterologous painting was demonstrated, and confirmed that swine chromosome 6 is syntenic to human chromosome 1p and 19q. A small insert genomic library of 1.39 x 106 clones was generated from the PCR amplified chromosome 6 genomic DNA and screened for (GT)n microsatellite genetic markers. Nine (GT)n microsatellite markers were developed and genotyped on a Yorkshire x Meishan swine reference family. All nine markers genetically mapped to chromosome 6, confirming the purity of the microisolation method. The method used here should be adaptable to the microdissection of subchromosomal regions of not only the swine genome but also other livestock genomes.