Türkiye’de Damızlık Olarak Kullanılan Siyah Alaca (Holstein) Irkı Boğalarda Gözlenen Genetik Darboğaz

Bir darboğaz ne kadar yakın zamanda olursa yönetim prosedürleriyle zararlı etkilerinden kaçınılması veya bu etkilerin en aza indirilme olasılığı o kadar yüksek olur. Sayıca çok büyük popülasyonların bile ciddi bir genetik darboğaz yaşaması muhtemeldir. Suni tohumlamanın yaygınlaşması ve küresel sperm ticareti yüksek verimli boğaların spermlerinin tüm dünyada baskın olarak kullanılmasına alt yapı oluşturmuştur. Dünyada sütçü ırk olarak en çok yetiştirilen Holstein ineklerin tohumlanmasında özellikle bazı ülkelerin yetiştirdiği boğalara ait spermler küresel çapta sıklıkla kullanılmaktadır. Yüksek verim elde etmek için uygulanan yoğun seleksiyon programları çoğunlukla allel kayıplarıyla sonuçlanmaktadır. Bu çalışmada Türkiye’de Holstein inek popülasyonşarını tohumlamak için kullanılan damızlık boğaların herhangi bir darboğaz etkisi altında kalıp kalmadığı araştırılmıştır. Bunun için Türkiye’de üretilen ve Türkiye’ye ithal edilen yüksek verimli 300 baş Holstein boğaya ait sperma materyal olarak kullanılmıştır. On mikrosatellit lokus temel alınarak Bottleneck v.1.2.02 programı aracılığıyla Aşamalı Mutasyon Modeli ve İki Fazlı Mutasyon Modeli altında İşaret ve Wilcoxon Testlerine tabi tutularak darboğaz değerlendirmesi yapılmıştır. Ayrıca Mod-Kayması analizi ile darboğazın yakın zamanda olup olmadığı da yorumlanmıştır. Buna istinaden 3 kıtada (Asya, Avrupa, Amerika) 13 ülke tarafından yetiştirilen toplam 300 baş Holstein boğanın geçmişte bir darboğaz etkisi altında kaldığı ancak bu darboğazın yakın zamanda gerçekleşmiş bir darboğaz olmadığı sonucuna varılmıştır.

Anahtar Kelimeler:

Damızlık boğa, Darboğaz, Mikrosatellit, Siyah Alaca

Observed Genetic Bottleneck in Holstein Bulls Used As Stud in Türkiye

The more recent a bottleneck occurs, the more likely it is that its harmful effects will be avoided or minimized by management procedures. Even very large populations are likely to experience a severe bottleneck. The spread of artificial insemination and the global sperm trade have provided worldwide use of the sperm from the high-yielding bulls. In Holstein cows, which are the most common dairy breeds, the sperm from bulls raised by especially some countries are used globally. In addition, intensive selection programs applied to obtain high yield often result in allele losses. In this study, it was investigated whether breeding bulls used to inseminate Holstein cows in Türkiye were under any bottleneck effect or not. For this purpose, sperm from 300 high-yielding Holstein bulls produced in and imported to Türkiye was used as the material of the study. The bottleneck assessment was carried out by using Sign and Wilcoxon Tests under Stepwise Mutation Model and Two-Phase Mutation Model using Bottleneck v.1.2.02 program based on ten microsatellite loci. In addition, Mode-Shift analysis has also been interpreted to understand whether the bottleneck is recent or not. Based on this, it was concluded that a total of 300 Holstein bulls bred by 13 countries in 3 continents (Asia, Europe, Americas) were under pressure of a bottleneck effect in the past, but this bottleneck did not occurred in the recent time.

Keywords:

Holstein, Stud bull, Bottleneck, Microsatellite,

PDF

___

Boichard, D., Ducrocq, V., ve Fritz, S. Sustainable dairy cattle selection in the genomic era. In Journal of Animal Breeding and Genetics 2015; 132 (2).
Cornuet, J. M., ve Luikart, G. Description and power analysis of two tests for detecting recent population bottlenecks from allele frequency data. Genetics 1996; 144(4), 2001–2014. Demir, E., ve Balcioglu, M. S. Genetic diversity and population structure of four cattle breeds raised in Turkey using microsatellite markers. Czech Journal of Animal Science 2019; 64(10), 411–419.
Di Rienzo, A., Peterson, A. C., Garza, J. C., Valdes, A. M., Slatkin, M., ve Freimer, N. B. Mutational processes of simple-sequence repeat loci in human populations. Proceedings of the National Academy of Sciences of the United States of America 1994; 91(8), 3166–3170.
Ellegren, H. Microsatellites: Simple sequences with complex evolution. Nature Reviews Genetics 2004; 5(6), 435–445.
FAO. Global Plan of Action for Animal Genetic Resources and the Interlaken Declaration. World’s Poultry Science Journal 2007.
Groeneveld, L. F., Lenstra, J. A., Eding, H., Toro, M. A., Scherf, B., Pilling, D., Negrini, R., Finlay, E. K., Jianlin, H., Groeneveld, E., ve Weigend, S. Genetic diversity in farm animals - A review. In Animal Genetics 2010 ; 41 (1).
Li, H., ve Roossinck, M. J. Genetic Bottlenecks Reduce Population Variation in an Experimental RNA Virus Population. Journal of Virology 2004; 78(19).
Luikart, G., Allendorf, F. W., Cornuet, J. M., ve Sherwin, W. B. Distortion of allele frequency distributions provides a test for recent population bottlenecks. Journal of Heredity 1998; 89(3), 238–247.
Luikart, G., ve Cornuet, J. M. (a). Empirical evaluation of a test for identifying recently bottlenecked populations from allele frequency data. Conservation Biology 1998; 12(1), 228–237.
Luikart, G., ve Cornuet, J. M. (b). Empirical evaluation of a test for identifying recently bottlenecked populations from allele frequency data. Conservation Biology 1998; 12(1).
Lynch, M., Ackerman, M. S., Gout, J., Long, H., Sung, W., Thomas, W. K., ve Foster, P. L. Genetic drift , selection and the evolution of the mutation rate. Nature Publishing Group 2016; 17(11), 704–714.
Nel, M., Chakraborty, R., ve Fuerst, P. A. Infinite allele model with varying mutation rate. Proceedings of the National Academy of Sciences of the United States of America 1976; 73(11), 4164–4168.
Notter, D. R. The importance of genetic diversity in livestock populations of the future. Journal of Animal Science 1999; 77(1), 61–69.
Ohta, T., ve Kimura, M. A model of mutation appropriate to estimate the number of electrophoretically detectable alleles in a finite population. Genetical Research 1973; 22(2), 201–204.
Philipsson, J. Standards and Procedures for International Genetic Evaluations of Dairy Cattle. Journal of Dairy Science 1987; 70(2), 418–424.
Piry, S., Luikart, G., ve Cornuet, J. M. BOTTLENECK: A computer program for detecting recent reductions in the effective population size using allele frequency data. Journal of Heredity 1999; 90(4), 502–503.
R Development Core Team. R Core Team (2020). R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. URL https://www.R-project.org/. In R Foundation for Statistical Computing 2019; (Vol. 2).
Sainudiin, R., Durrett, R. T., Aquadro, C. F., ve Nielsen, R. Microsatellite mutation models: Insights from a comparison of humans and chimpanzees. Genetics 2004; 168(1), 383–395.
Shelyov, A., Kopylov, K., Vdovychenko, Y., Kramarenko, S., ve Kramarenko, O. Formation of the genetic structure of cattle populations by single locus DNA fragments depending on their productivity direction and origin. Agricultural Science and Practice 2021; 8(3), 35–49.
Storz, J. F., ve Beaumont, M. A. Testing for genetic evidence of Population expansion and contraction: An empirical analysis of microsatellite DNA variation using a hierarchical Bayesian model. Evolution 2002; 56(1), 154–166.