The aim was to develop a panel of informative microsatellite markers that could subsequently be used in this or other similar projects for any study of this nature. For each chromosome we tested up a large number markers per sire (up to 30, depending upon the length of the chromosome) and chose a panel of markers for each sire for each chromosome that were heterozygous for that sire. In other words, each sire had panel of markers chosen per chromosome, but these marker sets differed between sires.
We then genotyped all progeny and all available grandparents for the markers we chose for that sire. The particular advantage of this approach is that we only genotype markers that are likely to be informative and we do not waste effort or resources genotyping markers that will not contribute information. This approach was successful in ensuring that our genotyping strategy was informative and cost-efficient.
The informativeness of our genotyped markers, i.e. the proportion of the time we can unambiguously trace chromosomal segments back to the parent of origin, was close to 0.7 across all regions genotyped.
In total we genotyped 139 markers, and just less than 50000 individual genotypes. The actual markers genotyped were:
- Chromosome 1: BMS835, ILSTS44, ILSTS29, MCM58, BMS963, RM65, BM6438, BMS2321, MAF64, ILSTS004, CSSM04, BMS4000, INRA11, BMS527, DB6, BMS4001, MCM137, BM7145, BM6506, BMS4008, SOX2, TGLA415, BM8246, RM509, MCM130, BMS4045, CSSM32, BM864, LSCV105, BMS1789, BM1824, BM3205, OarHH36, URB014
- Chromosome 2: CSSM47, FCB226, BM3412, BMS1341, BL1080, BMS678, TGLA10, BMS1591, BM81124, CP79, TEXAN2, FCB20, BMS1126, BMS2626, ARO28, BM6444, BMS356, FCB11
- Chromosome 3: BMS710, BMS2569, BM827, ILSTS42, AGLA293, FCB5, ILSTS22, BMC1009, KD0103, BL4, LYZ, IFNG, CP43, MAF23, CSRD111, BM8230, BMS1248, TEXAN15, BM6433, BMS772, BM2830
- Chromosome 5: TGLA176, RM006, TGLA48, TGLA303, BMS2258, BMS792, BM1853, SHP1, OarAE129, MCM527, CSRD2134, BMS1247
- Chromosome 14: TGLA357, TEXAN10, BMS2213, MT2, ILSTS10, BM8151, MCM133, BM7109, INRA63, ILSTS002, BMS833, LSCV30, MCMA19, BM6507
- Chromosome 18: MCM131, ILSTS52, VH54, BP33, HH47, BMC5221, TGLA337, OY15, TGLA122, ILSTS54, MCM38, OB2, MCMA26, CSSM018, OY5, DLK
- Chromosome 20: INRA132, DYA, MCMA36, CP73, BM1815, DRB1, OLADRB, OMHC1, BMS468, TGLA387, CSRD226, BM1818, BP34, HH56, MCMA23
- Chromosome 21: BMC2228, ILSTS19, INRA175, CP20, VH110, JP15, HH22, BMC1206, BMS1948
This set of markers was used in our population, and has formed the basis for subsequent studies in commercial populations of sheep in which we aim to independently verify our findings.
These markers are publicly available to anyone who wishes to use them. Applied within a sheep breeding context they can be used to enhance genetic progress ina variety of traits related to sheep health, product quality and performance.