Submitted to: Swine Chromosome 7 Workshop
Publication Type: Abstract Only
Publication Acceptance Date: 9/15/1995
Publication Date: N/A
Technical Abstract: Microsatellite marker production in cattle is currently an inefficient process. Approximately 40% of CT.GT dinucleotide repeats are less than 13, which reduce informativeness (polymorphism). The 40% of microsatellites flanked by SINE's also reduce informativeness since primers based on repetitive elements frequently yield genotypes that are difficult to interpret. We have increased the selection pool of microsatellite-contain randomly sheared DNA. Enrichment of the phagemid library with CA or GT primers resulted in 45% positive clones. The overall yield of primer pairs was 3.5% of total colonies screened compared to .09% from random libraries prepared in M13 bacteriophage which yield < 1% positive clones. The increase in primer (pair) yield was reflected in usefulness. Eight-six percent of the primer pairs were informative when typed in reference families containing diverse breeds compared to 76% from M13 bacteriophage libraries. Interestingly, enrichment of the phagemid library with tri- an tetranucleotide repeats did not provide an abundant source of highly polymorphic bovine microsatellite markers. Marker distribution (intervals) for 100 markers from libraries based on randomly sheared DNA was not different from 100 markers from M13 bacteriophage libraries prepared from DNA digested with MboI suggesting that skeletal coverage is not influenced by source of inserts. Enrichment of bovine genomic phagemid libraries provides large numbers of clones positive for microsatellites and improves our ability to rapidly extend the linkage maps for cattle and sheep.