Palani, Kalaiselvi

Panandam, Jothi Malar

Universiti Putra Malaysia Institutional Repository

Agricultural SCiencesMicrosatellite Analysis of the Mafriwal Dairy Cattle of MalaysiaPanandsm JM and Kslal5elvl PFacultyof AgricultureUniversiti Putra Malaysia43400 UPM, Serdang, SelangorMalaysiaTelephoneNumber of Corresponding Author: 03-89466896E-mail ojCorrespondingAuthor:jothi@agri.upm.edu.mvKey words: Mafriwal, Sahiwal-Friesian, micro satellite, variability, milkIntroductionThe genetic variability of a population or breed is an important element in deciding on breeding and genetic conservationstrategies. Molecular markers have been widely used to access genetic variability since they screen a wide region of thegenome. RFLP and microsatellites markers have been used to explain bovine domestication and migration patterns (Loftus etal., 1994; Bradley et al., 1994) and to characterise cattle populations (MacHugh et al., 1997; Kemenes et al., 1999).The Mafriwal dairy cattle of Malaysia is a tropicalised Sahiwal-Friesian crossbred with 50-75% Friesian genes. It has beendeveloped by the Department of Veterinary Services Malaysia as a high milk producing breed type, adapted to the hot andhumid local environment and resistant to local diseases. Since the Mafriwal is a new breed type, still under development andwith varying Friesian gene content, its gene pool is subjected to changes. There has been no study on its genetic (molecular)variability. It is essential that the genetic variation that exists in the Mafriwal be evaluated, monitored and utilized. Inaddition, to accelerate the genetic improvement of Mafriwal modem techniques of selection, such as marker assisted selection,may be adopted if markers linked to economically important quantitative trait loci are identified.The objectives of this study are to evaluate genetic variability of the Mafriwal dairy cattle of Malaysia using microsatellites,and to identify microsatellite markers that show association with important economic traits.Materials and MethodsBlood was randomly sampled from 40 Mafriwal cows at Institut Haiwan Kluang, Johor, of the Department of VeterinaryServices Malaysia. The DNA was extracted from the whole blood and analysed for 32 microsatellite loci selected from thecattle genome database (MARC, 2003).The Mafriwal cows available at the Institute were also ranked based on their milk production (average daily milk yield, totalmilk yield, lactation length and dry period). Blood samples were collected from 60 animals classified as the highest (30 .animals) and lowest (30 animals) milk producers. DNA was extracted from the blood and analysed for 10 polymorphicmicrosatellite loci, which have been suggested to be associated with milk production. In an attempt to investigated theassociations between the microsatellite alleles and the milk production traits, the average daily milk yield, total milk yield,lactation length and dry period of the two groups were compared with respect to presence or absence of alleles which werepredominant in one of the groups.Results and DiscussionThe microsatellite analysis generated 30 polymorphic loci (TGLA 53 and TGLAI16 were monomorphic). The number ofalleles per locus ranged from 4 (BM 1329) to 8 (BM2639). The mean observed allele number was 6.23 and the effective meanallele number was 5.02. The number of genotypes per locus ranged from 8 (B~1S 1716) to 19 (BM6425) with a mean 6.23 andmode 7. The genotypic frequencies ranged between 0.03 - 0.33. The observed heterozygosity per locus ranged from 0.38(MB002) to 0.78 (BRN); the mean was 0.55 and the modes 0.42 and 0.55. The mean overall heterozygosity was 0.79. Thelarge number of polymorphic loci with high allele number and heterozygosity indicates high genetic variability in theMafriwal. This may be partly attributed to Mafriwal being a relatively new breed type and comprising of animals with varyingFriesian gene content. The mean number of alleles per locus is similar to that reported by Bishop et al. (1994), 6.8 alleles perlocus from a survey of 468 microsatellite markers in 206 Bas taurus! Bas indicus animals. This suggests that microsatelliteloci in cattle show high variability, which in tum may be attributed to the fact that microsatellites may be situated at the noncoding regions of the genome and, therefore, are unaffected by the selection influencing functional genes. Significant(P<0.05) deviations from Hardy-Weinberg equilibrium were observed for all the polymorphic loci. This is as expected asanimals from other breeding farms are often introduced into this herd and. since this herd serves as a nucleus herd the animalsare subjected to selection.High and low milk producers did not vary in the number of alleles per locus or heterozygosity. There was no allele totallyabsent in one of the groups but in high frequency in the other that could be associated with one of the milk production locus.High producers with allele AI80 at HUJVI77 and low producers with allele D244 at MB002 had significantly (P<O.05) highertotal milk yield than their group members that lacked these alleles. When the data of both groups were pooled, the animalswith the absence of allele EI46 at UWCA26 and JI98 at BMI329 had significantly (P<O.05) higher total milk yield andaverage daily milk yield. The lack of clear association between the microsatellite markers and milk production traits may bedue to the small sample size used in the investigation and the small number of loci investigated. Furthermore, the large161UPM Research Report 1997-2000. Vol II.Section 2-Extended Abstractsnumber of alleles detected per locus made individual allele frequencies too low to observe any association. The associationsuggested by some of the alleles is confined to one group or the pooled data and is not observed for the individual groups.This too may be due to the low allele frequencies for the markers concerned.ConclusionsThe Mafriwal dairy cattle at Institut Haiwan Kluang shows high variability with respect to microsatellite loci. Since theMafriwal is still in the development stage, its genetic variability is expected to change and should be monitored. There was alack of clear association between the microsatellite markers and milk production traits. The possible association suggested bysome of the markers must be further investigated using more animals and pedigree data before any definite conclusions may bemade.Benefits from the studyThis is the first molecular evaluation of a Mafriwal population. It will serve as a reference for subsequent monitoring of thechanges in the genetic variability of this and similar populations.Some microsatellite markers have been identified in this study that may be further investigated for association with milkproduction traits. If the association is confirmed, they may be used in marker assisted selection which would accelerategenetic improvement of the Mafriwal.Patent(s), if applicable:NilStage of Commercialization, if applicable:NilProject Publications in Refereed Journals:NilProject Publications in Conference ProceedingsI. Kalaiselvi P, Panandam JM, Tan SG and Yusoff K. 2002. Association between microsatellite markers and milk production traits inMafriwal dairy cattle. Proceedings of the l21llScientific Meeting and 131llAnnual General Meeting of the Malaysian Society for MolecularBiologyand Biotechnology.2002; p 39 (abstract).Graduate ResearchNameGraduateof Research Topic Field of Expertise Degree Awarded Graduation YearKalaiselvi Palani Genetic Animal Geneticscharacterisation ofthe Mafriwal dairycattle of Malaysiausing quantitativeand molecularmethodsPh.D (working Anticipated 2004towards)IRPA Project numberOI-02-04-0379UPM Research Cluster:AFFProject Leader Jothi Malar Panandam162

Microsatellite analysis of the Mafriwal dairy cattle of Malaysia

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Microsatellite analysis of the Mafriwal dairy cattle of Malaysia

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