Studies On Heat-tolerance Candidate Markers Of S441 And S463 For Chinese Holstein Cattles

To determine genes or associated DNA markers underlying the heat-tolerance, Chinese Holstein catties were scanned by use of RAPD(randomamplified polymorphic DNA)technique.1. Obtain the RAPD markersIn this experiment, with DNA from strong heat-tolerance and weak heat-tolerance health Chinese Holstein cattle as material, was studying heat-tolerance in Holstein by using the technology of RAPD-PCR with selected 154 RAPD primers. The result indicated that two special segment which named as S441 and S463 had something to do with strong heat-tolerance.2. The detect result of RAPD markers in Holstein cattle46 head Holstein bull and 213 head Holstein cow useing S441 and S463 markers measured by us. To bull, 15 head had the S441 marker, 17 head had the S463 marker and 7 head for two. To cow, 27 head had the S441 marker, 64 head had the S463 marker and 9 for two.3. RAPD markers with the decline rate of milk yieldTo analysis the decline rate of milk yield for different markers. The result is that, for the cow which had S441 marker,S463 marke and none marker, the decline rate of milk yield were 3.51%,3.86% and 22.56% respectively. For the decline rate of milk yield, these cows which had the heat-tolerance candidate marker were lower than those cows which hadn't the marker, and the difference was significantly(P<0.05).4. RAPD markers with milk compositionButter fat rate,milk protein,milk sugar,dry matter were detected from May to Sep. In May, the butter fat rate and milk protein for those cow which had the RAPD markers were lower than other months, but it was higher than June and July for those cow which had not the RAPD marker .the milk sugar for those cow which had different markers had no significantly difference (P>0. 05) . In August, the dry matter for those cow which had different markers were lower than other months, and the difference were significantly (P<0.05). 5. Bioinformatics for RAPD markersRecollected and clone the two sequences which marked by S441 and S463, it was found that thesequences of S441 with KCNN2 gene had 89% homology, it may be intron 3 in KCNN2 gene . The sequences S463 with NW₀01508847.1 and NW₀01508757.1 had 99% homology. The function of NW₀01508847.1 and NW₀01508757.1 were unkown. Based on known function of the KCNN2 gene, it may be a candidate gene for heat-tolerance.