Genetic diversity in Egyptian and Italian goat breeds ... - CiteSeerX

J. Anim. Breed. Genet. ISSN 0931-2668

ORIGINAL ARTICLE

Genetic diversity in Egyptian and Italian goat breeds measured with microsatellite polymorphism S.H. Agha1, F. Pilla2, S. Galal1, I. Shaat3, M. D’Andrea2, S. Reale2, A.Z.A. Abdelsalam4 & M.H. Li5* 1 2 3 4 5 *

Department of Animal Production, Faculty of Agriculture, Ain Shams University, Shubra Alkhaima, Cairo, Egypt Department of Animal, Agricultural and Environmental Sciences, Faculty of Agriculture, Molise University, Campobosso, Italy Department of Sheep and Goat Research, Animal Production Research Institute, Agriculture Research Center, Dokki, Cairo, Egypt Department of Genetics, Faculty of Agriculture, Ain Shams University, Shubra Alkhaima, Cairo, Egypt Biotechnology and Food Research, MTT Agrifood Research Finland, Jokioinen, Finland present address: Ecological Genetics Research Unit, Department of Biological and Environment Sciences, PO Box 65, FIN-00014 University of Helsinki, Finland

Keywords Barki; Egyptian Baladi; genetic diversity; Maltese and Montefalcone goat; microsatellites; polymorphism; Zaraibi. Correspondence Ihab Shaat, Department of Sheep and Goat Research, Animal Production Research Institute, Agriculture Research Center, Nadi El-Said Street, 12311, Dokki, Cairo, Egypt. Tel: +202 3337 1994; Fax: +202 3760 0598; E-mail: [email protected] Received: 30 July 2007; accepted: 14 January 2008

Summary Seven microsatellite markers were used to study genetic diversity of three Egyptian (Egyptian Baladi, Barki and Zaraibi) and two Italian (Maltese and Montefalcone) goat breeds. The microsatellites showed a high polymorphic information content (PIC) of more than 0.5 in most of the locus–breed combinations and indicated that the loci were useful in assessing within- and between-breed variability of domestic goat (Capra hircus). The expected heterozygosity of the breeds varied from 0.670 to 0.792. In the geographically wider distributed Egyptian Baladi breed there were indications for deviations from random breeding. Analysis of genetic distances and population structure grouped the three Egyptian goat breeds together, and separated them from the two Italian breeds. The studied Mediterranean breeds sampled from African and European populations seem to have differentiated from each other with only little genetic exchange between the geographically isolated populations.

Introduction In Egypt, goats are an important source of meat. They are distributed across the country, especially dense in the Nile valley and delta and with lower concentration in the north-western coastal region and at oases (Galal et al. 2005). In the Nile valley goats are usually found in small holdings as mixed flocks with sheep and other farm animals like cattle and buffaloes, while in the north-western Mediterranean coast (Figure 1) they are in large herds mixed with sheep. Most of the livestock breeds in Egypt lack molecular characterization required for establishing adequate utilization of genetic variation in developing animal production. Goat genetic improvement schemes in Egypt have involved crossbreeding trials with examples Damascus goats and the development 194

of local breeds, in which the Zaraibi breed has been a recent target of joint work with the Food and Agriculture Organization of the United Nations (FAO). Animals were purchased from farmers and markets in different governorates to establish a research herd and a selection programme for a breed where special attention was paid to avoidance of inbreeding. The goat is among the earliest livestock species to have been domesticated approximately 9000 BP in Southeast Asia along the present Iran–Iraq borders (Mason 1981). Goats are spread over a wide range of habitats with a substantial concentration in the tropics and dry zones in developing countries (Galal 2005; FAOSTAT 2006). Therefore, they are expected to show a large amount of genetic diversity in adapting to the varying ecosystems. So far, the goat diversity studies based on microsatellites have been

ª 2008 The Authors Journal compilation ª 2008 Blackwell Verlag, Berlin • J. Anim. Breed. Genet. 125 (2008) 194–200

Genetic diversity in Egyptian and Italian goat breeds

S. H. Agha et al.

because of their high degree of polymorphism, random distribution across the genome and neutrality with respect to selection. Many bovine microsatellite markers have been used for genetic analysis in sheep and goats (Bruford & Wayne 1993). The objectives of the present study were to investigate the polymorphism in a set of microsatellites and to quantify the genetic diversity of three Egyptian and two Italian goat breeds. The three Egyptian breeds serve as part of a first attempt to describe the characteristics of molecular genetic variation in Egyptian goat populations in relation to breeds from the north shore of the Mediterranean. The two Italian breeds have been studied and documented by Iamartino et al. (2005). Materials and methods Animals

Figure 1 Geographical distribution of the studied goat breeds.

carried out on Swiss (Saitbekova et al. 1999) and Asian breeds (Barker et al. 2001; Ganai & Ydav 2001; Li et al. 2002; Li & Valentini 2004). Only recently, some attention has been paid to Mediterranean breeds (Iamartino et al. 2005; Canõn et al. 2006), although the area around the Mediterranean Sea has approximately 16% of the total goat breeds in the FAO list (http://www.fao.org/dad-is/), and for example, Italy is an important reservoir of goat diversity harbouring the second largest number (50) of goat breeds after China (http://www.fao.org/dadis/). There were very few studies done on the molecular genetic variation of African goat populations. Canõn et al. (2006) included Middle East goat population, however, in their study there were no breeds from the African continent, with the closest being two populations (Beeshi, Najrani) from Saudi Arabia. Thus, there is a need to extend the diversity studies to cover also African goat populations and find their position in the global goat diversity. The information on molecular genetic variation could help in understanding the relationship and diversity within and among the local Egyptian and Mediterranean breeds (Galal et al. 2005). The genetic distance measurement between the breeds can also be used to quantify genetic similarities between the breeds and even to proxy the expected heterosis gained in crossing the breeds (Toro & Ma¨ki-Tanila 2007). Employment of microsatellites is one of the most powerful means for studying the genetic diversity

Egyptian animals were sampled from three research stations where breed status is well known and the pedigree information has been maintained over several generations. The pedigree information was used to sample animals, which were unrelated. The stations belong to the Animal Production Research Institute (APRI) of Agriculture Research Center at the Egyptian Ministry of Agriculture. The breeds were Egyptian Baladi at Sakha station in the Nile delta, Zaraibi at El-Serw station in the north-eastern Egypt in the Nile delta, and Barki at Borg El-Arab station in the north-western coastal Mediterranean region of Egypt (Figure 1). Forty seven blood samples of Egyptian goats (Egyptian Baladi, 21; Barki, 14; and Zaraibi, 12) were collected using vactutainer tubes via the jugular vein. There were DNA samples available from the Italian goats, which were represented by 50 animals from Maltese breed and 29 from Montefalcone breed (Figure 1). Molecular analysis

Seven microsatellites (INRA005, ILSTS019, SRCRSP5, ILSTS087, CSRD247, HSC, INRA063) were used (Table 1). The markers were chosen on the basis of polymorphism, allele size range and ability to coamplify in PCR reactions in the earlier study on the Italian breeds (Iamartino et al. 2005), which included the breeds of Montefalcone and Maltese at the listed markers except HSC. Genotypes of the other microsatellites in the Italian breeds were obtained from the previous study of Iamartino et al. (2005). Four of the markers (SRCRSP5, ILSTS087, CSRD247, INRA063) appeared in the list of markers recommended by the


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Breed Egyptian Barki Zaraibi Microsatellite Baladi INRA005 ILSTS019 SRCRSP5

HSC

ILSTS087

CSRD247 INRA063 All

4 0.604 7 0.797 8 0.762

4 3 0.541 0.511 6 4 0.617 0.221 6 6 0.697 0.672 177:8.33 7 9 0.714 0.844

13 0.874 268:5.88 296:2.94 9 5 7 0.764 0.597 0.770 7 0.788 5 0.578 53

7 4 0.758 0.694 4 4 0.651 0.482 39 37

Maltese

Montefalcone All References

4 0.394 6 0.703 11 0.691 163:1.06 10 0.794 300:2.04

4 0.607 6 0.619 6 0.608

8 0.791 155:17.78 8 0.669 4 0.631 51

4 Vaiman et al. (1992) 8 Kemp et al. (1995) 12 Arevalo et al. (1994)

10 0.781

16 de Gortari et al. (1997)

8 0.587

11 Kemp et al. (1995)

8 0.734 5 0.590 47

10 Kemp et al. (1995) 5 Vaiman et al. (1994) 66

Guidelines for Development of National Farm Animal Genetic Resources Management Plans of the FAO (Measurement of Domestic Animal Diversity, MoDAD; http://www.fao.org/dad-is/). DNA was extracted from blood using standard phenol-chloroform extraction method (Sambrook et al. 1989). PCR reactions were performed in a final volume of 10 ll containing 200 lM dNTPs, 0.1 ll of a 5 U ⁄ ll of Ampli-Taq (Applied Biosystems, Foster City, CA, USA), 1.5 mM MgCl2, 1 · PCR buffer, 5–25 lM of each primer and 20–50 ng of genomic DNA. Amplified fragments were separated by capillary electrophoresis using an ABI PRISM310 automatic sequencer (Applied Biosystems, Foster City, CA, USA). Fluorescently-labelled fragments were detected and sized using GeneMapper (version 3.7) (Applied Biosystems). Statistical analysis

Frequencies and number of alleles for each locus, private alleles in each population, observed and expected heterozygosity, Wright’s statistics FIS and FST were estimated using fstat (version 2.9.3.2) (Goudet 2002). GENEPOP (version 3.4) (Raymond & Rousset 1995) was used to estimate Hardy–Weinberg equilibrium (HWE) over loci within each population. The polymorphic information content (PIC) value was calculated according to Botstein et al. (1980). Nei’s (1987) standard genetic distances among 196

Table 1 Number of alleles (bold), polymorphic information content and the size (bp) and frequency (%) of private alleles (italics) of the microsatellites in the Egyptian and Italian goat breeds

populations were computed by popgene (version 1.31) (Yeh et al. 1999). A pairwise matrix of the genetic distances was then used to obtain a neighbour-joining (NJ) tree (Saitou & Nei 1987), which was visualized using the software TreeView (Page 1996). Bootstraps of 1000 replicates were performed in order to test the robustness of tree topology using the dispan program (Ota 1993). The population structure was evaluated based on a Bayesian clustering analysis by employing the structure program (Pritchard et al. 2000). This method uses multilocus genotypes to infer for all the individuals and populations the fractions in their genetic ancestry that belong to a given number (k) of clusters. A Monte Carlo Markov chain was run for k = 2, 3, 4 or 5 with a burn-in period of 20 000 and a run length of 20 000 iterations. A default setting assuming an admixture model with correlated allele frequencies was used in all runs. The graphical display of the structure results was generated using distruct software (Rosenberg 2004). Results and discussion Variation at microsatellite markers

Microsatellites used in the present study were polymorphic in all the breeds (Table 1). The highest number of alleles (16) was at HSC and the lowest (4) at INRA005. Egyptian Baladi had the highest number of alleles at the loci, which may be due to genetic



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exchange between the widely distributed Egyptian Baladi goats and other goat populations in the Nile valley and delta region. Maltese breed also possessed a high number of alleles. The breed originates on the island of Malta and has probably been crossed with North-African goat populations (Iamartino et al. 2005). Barki & Zaraibi breeds had smaller numbers of alleles. The home tracts of these two breeds are in more restricted areas. All the markers were highly informative in the studied breeds (PIC > 0.50), except ILSTS019 in Zaraibi (PIC = 0.221), INRA005 in Maltese (PIC = 0.394), and INRA063 in Zaraibi (PIC = 0.482). Microsatellites with high PIC are useful in genetic diversity studies. In this study private alleles were found in Egyptian Baladi, Zaraibi and Maltese (Table 1). However, Iamartino et al. (2005) found private alleles in both Maltese and Montefalcone breeds. There are several reasons for the existence of private alleles, like multi-origin of the breeds, little subsequent genetic exchange between them or genetic drift. The highest frequency of a private allele was 0.178 at ILSTS087 (155 bp) in Maltese, so that genetic drift may explain the observed differentiation between the breeds. The small size of population samples prevents us from making any definite explanations for the observed values. Within breed variation

Genetic variability within the breeds is relatively high, as evidenced by the high mean expected heterozygosity (0.722) (Table 2). It is of a similar magTable 2 Number of animals (n), mean observed number (na) (and SD) of alleles, mean (and SE) of observed (Hobs) and expected heterozygosity (Hexp), the exact test for Hardy-Weinberg equilibrium (HWE) and Wright’s FIS in Egyptian and Italian goat breeds Breed

n

Egyptian Baladi

21

Barki

14

Zaraibi

12

Maltese

50

Montefalcone

29

All

1

126

na

Hobs

Hexp

HWE test1

FIS2

7.6 (2.9) 5.6 (1.3) 5.3 (2.1) 7.2 (2.8) 6.7 (2.1) 6.5 (2.2)

0.662 (0.040) 0.660 (0.051) 0.612 (0.054) 0.685 (0.026) 0.660 (0.033) 0.654 (0.041)

0.792 (0.034) 0.724 (0.028) 0.670 (0.085) 0.724 (0.053) 0.701 (0.025) 0.722 (0.045)

0.0028

0.168*

0.0064

0.091NS

0.3202

0.094NS

0.0016

0.068NS

0.1157

0.057NS

–

0.096NS

All the test values were highly significant, p < 0.001. NS = not significant, p ‡ 0.05; *Significant, p < 0.05.

2

nitude as the average expected heterozygosity of 0.68 in the Brown Short Haired goat reported by Jandurova´ et al. (2004). In Chinese goats the expected genetic heterozygosity varied from 0.611 to 0.784 (Li et al. 2002). Our diversity results are within the ranges found in a study on the goat breeds in Europe and in Saudi Arabia (Canõn et al. 2006). In assessing diversity estimates from different studies, it should be mentioned that the values are not directly comparable, as different microsatellites have been used. There were three common microsatellites with Canõn et al. (2006), two with Li et al. (2002) and none with Jandurova´ et al. (2004). Hence the comparisons have only suggestive indications. The high genetic diversity observed in a breed could be explained by overlapping generations, mixing of populations from different geographical locations, natural selection favouring heterozygosity or subdivision accompanied by genetic drift (Toro & Ma¨ki-Tanila 2007). The effect of these factors is more pronounced when the effective population size is very large. The expected heterozygosity was the highest (0.792) in Egyptian Baladi. A wide distribution of this breed across the country increases the likelihood for the enrichment of different alleles in the geographically widely scattered population. The Egyptian breeds are very close to the domestication centre of goats in the near East (Zeder & Hesse 2000) and therefore, they are expected to have maintained relatively high genetic diversity. Mean observed heterozygosity was lower than the expected in all the studied breeds, and deviation from HWE was significant in all of them (Table 2). Heterozygosity deficit within a population, as measured by Wright’s FIS, was positive in all the breeds when averaged across the loci, and ranged from 0.057 in Montefalcone to 0.168 in Egyptian Baladi (Table 2). The Egyptian breeds had higher FIS values than the Italian breeds did. The variation at the microsatellite markers indicated deviations from random mating in the three sampled Egyptian breeds, although measures are practiced to avoid inbreeding, like restricting the use of same sires, exchanging sires between the stations and adding new ‘blood’ from outside the stations. Genetic differentiation among breeds

Pairwise genetic differentiations quantified by FST estimates ranged from 0.042 between Egyptian Baladi and Barki to 0.149 between Zaraibi and Montefalcone, and similarly Nei’s (1987) standard genetic distance varied between 0.160 and 0.493 (Table 3).


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Table 3 Estimated pairwise FST as a measure of genetic differentiation (above diagonal) and Nei’s (1987) standard genetic distance (below diagonal) among Egyptian and Italian goat breeds Egyptian Baladi Barki

Egyptian Baladi Barki Zaraibi Maltese Montefalcone

0.042NS – 0.172 0.265 0.303

– 0.160 0.163 0.291 0.223

Zaraibi

Maltese Montefalcone

0.051* 0.061NS – 0.367 0.493

0.077** 0.080** 0.114** – 0.338

0.067** 0.095** 0.149** 0.103** –

NS = not significant, p ‡ 0.05; *significant, p < 0.05; **highly significant, p < 0.01.

Figure 2 Neighbour-joining tree with 1000 bootstraps on Nei’s (1987) standard genetic distances. Bootstrap values are reported as percentages.

Conclusions

k=3 198

The Egyptian goat breeds, especially the Egyptian Baladi breed with a wider distribution across the Nile valley and delta, is possessing high genetic variability. The study is indicating that the analyzed Mediterranean goat breeds have been genetically differentiated in line with their geographical separations. Most likely there has been only little genetic exchange between the goat populations in the region. This study is the first attempt to characterize the molecular genetic variability of the Egyptian goat

Maltese

Zaraibi

Barki

Egyptian baladi

Montefalcone

Maltese

Zaraibi

Barki

Egyptian baladi

Genetic differentiation (FST) between Egyptian breeds is very small, reflecting a high genetic similarity among these breeds, while they are differentiated from the Italian ones. The Italian breeds are genetically diverged from each other (Table 3). When the breed relationships are visualized with the dendrogram (Figure 2), Egyptian Baladi and Zaraibi are together with Barki deviating from the pair – still with a low bootstrap value (48%). The Barki goat is a desert breed that lives in the north-western coastal region of Egypt, while both Egyptian Baladi and

k=4

Montefalcone

Population

Zaraibi goats are Nile valley and delta breeds (Figure 1). There is only weak differentiation among the Egyptian breeds, while the phylogenetic tree shows a clearer differentiation between the Egyptian and the Italian breeds (Figure 2). Bayesian analysis of the data with a structure program (Pritchard et al. 2000) showed that the samples had the highest estimated likelihood at k = 3 and running the program at k = 4 did not detect any additional cluster (Figure 3). Thus, three genetic clusters were identified, that is, two monophyletic clusters coinciding with the two Italian breeds and a cluster of the three Egyptian breeds. Genetic clustering of the populations is consistent with the phylogenetic dendrogram (Figure 2). Our results indicated that genetic components of the three Egyptian goat breeds are quite similar, which can be due to little genetic divergence among them after their immigration into Egypt out of the domestication centre in the Near East. This speculation was also seen as a higher level of genetic diversity in the three breeds.

Figure 3 The clustering outcomes for all samples at k = 3 and k = 4. The length of the segment in white, light grey, dark grey, or black shows the individual’s estimated proportion of membership in that cluster. Black lines separate the individuals of different breeds. Populations are labelled above.



S. H. Agha et al.

populations. There is a need for a more thorough analysis of the goat genetic diversity in the region by including more breeds, larger sample sizes and additional molecular markers. In terms of improving the efficiency of Egyptian goat production, we have observed that the populations have a similar amount of genetic variation as other goat breeds, when extrapolated from the information on microsatellite markers. The Nile valley ⁄ delta breeds are distinct from the desert breed and would all deserve an independent improvement schemes. The Egyptian breeds are exhibiting a generally high prolificacy and therefore there is no need to make any efforts to bring additional or compensatory gains in such a low-heritability trait (which would need more time to change through withinpopulation selection) via a crossbreeding programme, as such a program brings along the risk of losing other well identified and beneficial characteristics in well established breeds. Acknowledgements A part of this work was prepared through a scholarship from the Framework of the Individual Mobility Grant of Education and Training Programs and Actions (TEMPUS), European Commission. Special thanks are due to Ms. Asmaa Aboshady and Ms. Hend Abo-Elazm for helping in running the laboratory work. Dr Ahmad EL-Beltagi’s help in the statistical analysis is acknowledged. We would also like to thank the two anonymous referees and the editor for very useful comments on the earlier versions of the manuscript. References Arevalo E., Holder D.A., Derr J.N., Bhebhe E., Linn R.A., Ruvuna F., Davis S.K., Taylor J.F. (1994) Caprine microsatellite dinucleotide repeat polymorphisms at the SR-CRSP -1, SR-CRSP-2, SR-CRSP-3, SR-CRSP-4 and SR-CRSP-5 loci. Anim. Genet., 25, 202. Barker J.S.F., Tan S.G., Moore S.S., Mukherjee T.K., Matheson J.L., Selvaraj O.S. (2001) Genetic variation within and relationships among populations of Asian goats (Capra hircus). J. Anim. Breed. Genet., 118, 213–223. Botstein D., White R.L., Skolnick M., Davis R.W. (1980) Construction of a genetic linkage map in man using restriction fragment length polymorphism. Am. J. Hum. Genet., 32, 314–331. Bruford M.W., Wayne R.K. (1993) Microsatellites and their application to population genetic studies. Curr. Opin. Genet. Dev., 3, 939–943.

Canõn J., Garcıá D., Garcıá-Atance M.A., Obexer-Ruff G., Lenstra J.A., Ajmone-Marsan P., Dunner S., the Econogene Consortium (2006) Geographical partitioning of goat diversity in Europe and the Middle East. Anim. Genet., 37, 327–334. FAOSTAT (2006) CD-ROM. Food and Agriculture Organization of the United Nations, Rome, Italy. Galal S. (2005) Biodiversity in goats. Small Rumin. Res., 60, 75–81. Galal S., Abdel-Rasoul F., Anous M.R., Shaat I. (2005) On-station characterization of small ruminant breeds in Egypt. In: L. In˜iguez (ed.), Characterization of Small Ruminant Breeds in West Asia and North Africa, Vol. 2. ICARDA, Aleppo, Syria, pp.141–193. Ganai N.A., Ydav B.R. (2001) Genetic variation within and among three Indian breed goat 138 using heterologous microsatellites markers. Anim. Biotech., 12, 121–136. de Gortari M.J., Freking B.A., Kappes S.M., Leymaster K.A., Crawford A.M., Stone R.T., Beattie C.W. (1997) Extensive genomic conservation of cattle microsatellite heterozygosity in sheep. Anim. Genet., 28, 274–290. Goudet J. (2002) FSTAT (version 2.9.3.2): a program to Estimate and Test gene Diversities and Fixation Indices. Available from http://www.unil.ch/izea/software/ fstat.html. Updated from Goudet (1995). Iamartino D., Bruzzone A., Lanza A., Blasi M., Pilla F. (2005) Genetic diversity of Southern Italian goat populations assessed by microsatellite markers. Small Rumin. Res., 57, 249–255. Jandurova´ O.M., Kott T., Kottova´ B., Cezrnekova´ V. (2004) Seven microsatellite markers useful for determining genetic variability in White and Brown ShortHaired goat breeds. Small Rumin. Res., 52, 271–274. Kemp S.J., Hishida O., Wambugu J., Rink A., Longeri M.L., Ma R.Z., Da Y., Lewin H.A., Barendse W., Teale A.J. (1995) A panel of polymorphic bovine, ovine and caprine microsatellite markers. Anim. Genet., 26, 299– 306. Li X.L., Valentini A. (2004) Genetic diversity of Chinese indigenous goat breeds based on microsatellite markers. J. Anim. Breed. Genet., 121, 350–355. Li M.H., Zhao S.H., Bian C., Wang H.S., Wei H., Liu B., Yu M., Fan B., Chen S.L., Zhu M.J., Li S.J., Xiong T.A., Li K. (2002) Genetic relationships among twelve Chinese indigenous goat populations based on microsatellite analysis. Genet. Sel. Evol., 34, 729–744. Mason I.L. (1981) Classification and distribution of goat breeds. In: K. Maijala (ed.), Genetic Resources of Pig, Sheep and Goats. World Animal Science B8. Elsevier, Amsterdam, pp.8. Nei M. (1987) Molecular Evolutionary Genetics. Columbia University Press, New York, USA. Ota T. (1993) DISPAN: Genetic Distance and Phylogenetic Analysis Software. Institute of Molecular Evolu-


199


S. H. Agha et al.

tionary Genetics, Pennsylvania State University, Pennsylvania, USA. Page R.D.M. (1996) TREEVIEW: an application to display phylogenetic trees on personal computers. Comp. Appl. Biosci., 12, 357–358. Pritchard J.K., Stephens M., Donnelly P. (2000) Inference of population structure using multilocus genotype data. Genetics, 155, 945–959. Raymond M., Rousset F. (1995) GENEPOP: (version 1.2): population genetics software for exact tests and ecumenicism. J. Hered., 86, 248–249. Rosenberg N.A. (2004) DISTRUCT: a program for the graphical display of population structure. Mol. Ecol. Notes, 4, 137–138. Saitbekova N., Gaillard C., Obexer-Ruff G., Dof G. (1999) Genetic diversity in Swiss goat breeds based on microsatellite analysis. Anim. Genet., 30, 36–41. Saitou N., Nei M. (1987) The neighbour-joining method: a new method for reconstructing phylogenetic trees. Mol. Biol. Evol., 4, 406–425. Sambrook J., Fritsch E.F., Maniatis T. (1989) Molecular Cloning: A Laboratory Manual. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York, USA.

200

Toro M., Ma¨ki-Tanila A. (2007) Genomics reveals domestication history and facilitates breed development. In: K. Oldenbroek (ed.), Utilization and Conservation of Farm Animal Genetic Resources. Wageningen Academic Publishers, Wageningen, The Netherlands, pp. 75–102. Vaiman D., Osta D., Mercier D., Grohs C., Leveziel H. (1992) Characterization of five new bovine microsatellite repeats. Anim. Genet., 23, 537–541. Vaiman D., Mercier D., Moazami-Goudarzi K., Eggen A., Ciampolini R., Lepingle A., Velmala R., Kaukinen J., Varvio S.L., Martin P. (1994) A set of 99 cattle microsatellites: characterization, synteny mapping, and polymorphism. Mamm. Genome, 5, 288–297. Yeh F.C., Yang R.C., Boyle T. (1999) POPGENE (version 1.31): A Microsoft Windows-based Freeware for Population Genetic Analysis. University of Alberta and the Centre for International Forestry Research, Edmonton, Canada. Zeder M.A., Hesse B. (2000) The initial domestication of goats (Capra hircus) in the Zagros mountains 10,000 years ago. Science, 287, 2254–2257.
