Reduced genetic structure of north Ethiopian cattle revealed by Y-chromosome analysis

Abstract

Ethiopia is considered to be a putative migratory corridor for both Near-East Bos taurine and Arabian and Indian B. indicus cattle into East Africa. African pastoralism, which is associated with adaptation to specific habitats and farming systems, has contributed to the composite constitution of Ethiopian cattle. We analyse, for the first time, five Ychromosome microsatellite markers from seven north Ethiopian cattle populations, using a European Holstein-Friesian population as a reference, to assess the paternal gene pool and to explore the mechanisms behind the genetic structure. Our results reveal that the indicine alleles predominate in the present populations, with only one animal in the Arado carrying the taurine alleles. The north Ethiopian cattle populations with one exception (Abergelle) are characterized by a general low Y-chromosome haplotype diversity, as well as by a reduced interpopulation variance (F ST ¼ 4.0%), which can be a result of strong male-mediated selective sweeps. Population structure revealed by multidimensionalscaling analysis differentiates two populations (Arado and Abergelle) from the rest. Analysis of molecular variance does not lend support to the traditional classification for the populations, which is mainly based on physical characteristics. A network analysis indicates two closely related founding haplotypes accounting for a large proportion (50.0% in Abergelle and 85.0-94.7% in others) of north Ethiopian cattle Y-chromosomes. Our findings point to a common, but limited, paternal origin of the north Ethiopian cattle populations and strong male-mediated gene flow among them. The findings also provide insight into the historical immigration of cattle into East Africa.

Y chromosome analysis of native Turkish cattle breeds by microsatellite markers

“…A total of 7 Y-specific microsatellite loci and 2 fluorescence-labeled M13 primers (Table 1) were selected from previous studies (Liu et al, 2003;Li et al, 2007;Ginja et al, 2009). For pigtailing, the forward primers were synthesized with tails that matched one of the fluorescence-labeled M13 primers.…”

“…The understanding of the origin, relationships, and paternal inheritance of native breeds indicated that there is large share of Y chromosome-specific markers (Edwards et al, 2000;Hellborg and Ellegren, 2004;Li et al, 2007). Y chromosome-specific markers are preferred for testing paternity, examining contamination risks of DNA samples (analysis of male component in male/female mixtures), and handling criminal cases (Jobling et al, 1997;Gill et al, 2001;Jobling, 2001).…”

“…The Y chromosome follows paternal ancestry and is often investigated for determination of paternal origins (Li et al, 2007). The first analysis of the Y chromosome was made based on karyological features of different species and it was identified as metacentric/submetacentric and acrocentric in taurine (Bos taurus) and zebu (Bos indicus), respectively (Potter and Upton, 1979;Halnan and Watson, 1982).…”

Maternal and paternal genealogy of Eurasian taurine cattle (Bos taurus)

“…Frequency differences in alleles at Y-chromosomal microsatellites and in Y-chromosomal microsatellite haplotypes have been found in cattle (Edwards et al, 2000;Li et al, 2007b), suggesting their applicability for genetic diversity studies of domestic cattle. In addition to the more recent evolutionary events, Y-chromosomal microsatellites may have a potential to identify deeper lineages of Y-chromosomes (Bosch et al, 1999).…”

“…These data do not support the recent hypothesis on the origin of Y1 from the local European hybridization of cattle with male aurochsen. Compared with mtDNA, the intensive culling of breeding males and male-mediated crossbreeding of locally raised native breeds has accelerated loss of Ychromosomal variation in domestic cattle, and affected theIntroduction Analyses of mitochondrial DNA (mtDNA) D-loop sequences and Y-chromosome-specific polymorphisms (such as single nucleotide polymorphisms, insertiondeletion mutations and microsatellites) have indicated that humpless taurine (Bos taurus) and humped zebu cattle (B. indicus) have clearly distinguishable mtDNA and Y-chromosomal haplotypic profiles Bradley et al, 1996;Hanotte et al, 1997;Mannen et al, 2004;Götherström et al, 2005;Li et al, 2007b). This observation points towards two independent domestication events from genetically differentiated aurochs (B. primigenius) populations for the two basic taxa of domestic cattle.…”