Linkage disequilibrium between MHC-linked microsatellite loci in White Karaman, Awassi and Merinolandschaf sheep breeds

Sunulan çalışmada, Akkaraman, İvesi ve Merinolandschaf koyun ırklarında Büyük Doku Uyuşum Komplexi (MHC) ile bileşik olan ve olmayan mikrosatellit lokusları açısından bileşiklik dengesizliği olup olmadığı araştırıldı. Toplam 108 karşılaştırmada normal ve toplulaştırılmış analiz sonucunda sırasıyla altı ve yedi tane lokus çifti arasında önemli bileşiklik dengesizliği tespit edildi (p < 0,05). Normal ve toplulaştırılmış analiz sonucunda önemli sapmalardan sırasıyla yalnız ikisi ve üçünün MHC ile birleşik lokuslar arasında olduğu bulundu. Sonuç olarak araştırmaya konu olan populasyonlarm incelenen lokuslar açısından büyük oranda denge durumunda bulunduğu ve MHC ile birleşik lokuslar arasındaki bileşiklik dengesizliğinin seleksiyon yoluyla sürdürülmediği kanısına varıldı.

Akkaraman, Ivesi ve Merinolandschaf koyun ırklarında MHC ile bileşik mikrosatellit lokusları arasında bileşiklik dengesizliği

The purpose of this study was to examine the presence of linkage disequilibrium between nine microsatellite loci in and out of Major Histocompatibility Complex (MHC) as a description of population structure in White Karaman, Awassi and Merinolandschaf sheep populations. Of the 108 pairwise comparisons a significant linkage disequilibrium was observed between six and seven loci pair after exact test and pooling, respectively. Only two and three of the significant deviations were present between MHC-linked loci. The results indicated that the populations analyzed in this study were mostly in equilibrium and that selection did not play a major role to maintain the linkage disequilibrium between MHC-linked loci in the populations studied.

PDF

___

1. Jorde LB. Linkage disequilibrium and search for complex disease genes. Genome Research 2000; 10:1435-1444.
2. Luikart G, Buji-Duval MP, Ertugrul O et al. Power of 22 microsatellite markers in fluorescent multiplexes for parentage testing in goats (Capra hircus). Animal Genetics 1999; 30: 431-438.
3. Hughes AL and Nei M. Pattern of nucleotide substitution at major histocompatibility complex class I loci reveals overdominant selection. Nature 1988; 335:167-170
4. Paterson S, Wilson K and Pemberton JM. Major histocompatibility complex variation associated with juvenile survival and parasite resistance in a large unmanaged ungulate population (Ovis aries L.). Proceedings of the National Academy of Sciences USA 1998; 95: 3714-3719.
5. Outteridge PM, Andersson L, Douch PGC et al. The PCR typing of MHC-DRB genes in the sheep using primers for an intronic microsatellite: Application to nematode parasite resistance. Immunology and Cell Biology 1996; 74: 330-336
6. Schwaiger FW, Gostomski D, Stear MJ et al. An ovine major histocompatibility complex DRB1 allele is associated with low faecal egg counts following natural, predominantly Ostertagia circumcincta infection. International Journal of Parasitology 1995; 25- 815-822
7. Kalinowski ST and Hedrick PH. Estimation of linkage disequilibrium for loci with multiple alleles: basic approach and an application using data from bighorn sheep. Heredity 2001; 87: 698-708.
8. Paterson S. Evidence for Balancing Selection at the Major Histocompatibility Complex in a Free-Living Ruminant. The Journal of Heredity 1998; 89: 289- 294.
9. Schlötterer C. Evolutionary dynamics of microsatellite DNA. Chromosoma 2000; 109: 365- 371.
10. Bishop MD, Kappes SM, Keele JW et al. A genetic linkage map for cattle. Genetics 1994; 136: 619-639.
11. Brezinsky L, Kemp SJ and Teale AJ. ILSTS005: a polymorphic bovine microsatellite. Animal Genetics 1993; 24: 73.
12. Brezinsky L, Kemp SJ and Teale AJ. Five polymorphic bovine microstellites (ILSTS010-014). Animal Genetics 1993; 24: 75-76.
13. Kemp SJ, Hishida O, Wambugu J et al. A panel of polymorphic bovine, ovine and caprine microsatellite markers. Animal Genetics 1995; 26: 299-306.
14. Kappes SM. Utilization of gene mapping information in livestock animals. Theriogenology 1999; 51: 135- 147.
15. Maddox JF, Davies KP, Crawford AM et al. An enhanced linkage map of the sheep genome comprising more than 1000 loci. Genome Research 2001; 11: 1275-1289.
16. Mahdy EA, Mäkinen A, Chowdhary BP, et al. Chromosomal localisation of the ovine major histocompatibility complex (OLA) by in situ hybridisation. Hereditas 1989; 111: 87-90.
17. Schwaiger FW, Buitkamp J, Weyers E, et al. Typing of artiodactyl MHC-DRB genes with the help of intronic simple repeated DNA sequences. Molecular Ecology 1993; 2: 55-59.
18. Buitkamp J, Filmether P, Stear MJ, et al. Class I and class II major histocompatibility complex alleles are associated with faecal egg counts following natural, predominantly Ostertagia circumcincta infection. Parasitological Research 1996; 82: 693-696.
19. Groth DM and Wetherall JD. Dinucleotide repeat polymorphism within the ovine major histocompatibility complex class I region. Animal Genetics 1994; 25: 61.
20. Groth DM and Wetherall JD. Dinucleotide repeat polymorphism adjacent to sheep complement factor B. Animal Genetics 1995; 26: 282-283.
21. Raymond M and Rousset F. GENEPOP (Version 1.2): Population genetics software for exact tests and ecumenicism. The Journal of Heredity 1995; 86: 248- 249.
22. Crawford AM, Dodds KG, Ede AJ, et al. An Autosomal Genetis Linkage Map of the Sheep Gemome. Genetics 1995; 140: 703-724.
23. Falconer DS and Mackay TFC. Introduction to quantitative genetics. Longman, Harlow; 1996.
24. Farnir F, Coppieters W, Arranz JJ et al. Extensive genome-wide linkage disequilibrium in cattle. Genome Research 2000; 10: 220-227.
25. Tenesa A, Knott SA, Ward D, et al. Estimation of linkage disequilibrium in a sample of the United Kingdom dairy cattle population using unphased genotypes. Journal of Animal Science 2003; 81: 617- 623.
26. Ohta T. Linkage disequilibium due to random genetic drift in finite subdivided populations. Proceedings of the National Academy of Sciences USA 1982; 79: 1940-1944.
27. Lehmann T, Hawley WA and Collins FH. An Evaluation of Evolutionary Constraints on Microsatellite Loci Using Null Alleles. Genetics 1996; 144: 1155-1163