Mitochondrial DNA variants of Podolian cattle breeds testify for a dual maternal origin.
ABSTRACT: Over the past 15 years, 300 out of 6000 breeds of all farm animal species identified by the Food and Agriculture Organization of the United Nations (FAO) have gone extinct. Among cattle, many Podolian breeds are seriously endangered in various European areas. Podolian cattle include a group of very ancient European breeds, phenotypically close to the aurochs ancestors (Bos primigenius). The aim of the present study was to assess the genetic diversity of Podolian breeds and to reconstruct their origin.The mitochondrial DNA (mtDNA) control-regions of 18 Podolian breeds have been phylogenetically assessed. Nine non-Podolian breeds have been also included for comparison.The overall analysis clearly highlights some peculiarities in the mtDNA gene pool of some Podolian breeds. In particular, a principal component analysis point to a genetic proximity between five breeds (Chianina, Marchigiana, Maremmana, Podolica Italiana and Romagnola) reared in Central Italy and the Turkish Grey. We here propose the suggestive hypothesis of a dual ancestral contribution to the present gene pool of Podolian breeds, one deriving from Eastern European cattle; the other arising from the arrival of Middle Eastern cattle into Central Italy through a different route, perhaps by sea, ferried by Etruscan boats. The historical migration of Podolian cattle from North Eastern Europe towards Italy has not cancelled the mtDNA footprints of this previous ancient migration.
Project description:Analysis of DNA from archeological remains is a valuable tool to interpret the history of ancient animal populations. So far most studies of ancient DNA target mitochondrial DNA (mtDNA), which reveals maternal lineages, but only partially the relationships of current breeds and ancient populations. In this study we explore the feasibility of nuclear DNA analysis. DNA was extracted from 1000-years old cattle bone collected from Ferento, an archeological site in central Italy. Amplification of 15 microsatellite FAO-recommended markers with PCR products yielded genotypes for four markers. Expected heterozygosity was comparable with values of modern breeds, but observed heterozygosity was underestimated due to allelic loss. Genetic distances suggested a position intermediate between (1) Anatolian, Balkan, Sicilian and South-Italian cattle and (2) the Iberian, North-European and Central-European cattle, but also a clear relationship with two central-Italian breeds, Chianina and Romagnola. This suggests that these breeds are derived from medieval cattle living in the same area. Our results illustrate the potential of ancient DNA for reconstructing the history of local cattle husbandry.
Project description:The Etruscan culture developed in Central Italy (Etruria) in the first millennium BC and for centuries dominated part of the Italian Peninsula, including Rome. The history of the Etruscans is at the roots of Mediterranean culture and civilization, but their origin is still debated: local or Eastern provenance? To shed light on this mystery, bovine and human mitochondrial DNAs (mtDNAs) have been investigated, based on the well-recognized strict legacy which links human and livestock populations. In the region corresponding to ancient Etruria (Tuscany, Central Italy), several Bos taurus breeds have been reared since historical times. These breeds have a strikingly high level of mtDNA variation, which is found neither in the rest of Italy nor in Europe. The Tuscan bovines are genetically closer to Near Eastern than to European gene pools and this Eastern genetic signature is paralleled in modern human populations from Tuscany, which are genetically close to Anatolian and Middle Eastern ones. The evidence collected corroborates the hypothesis of a common past migration: both humans and cattle reached Etruria from the Eastern Mediterranean area by sea. Hence, the Eastern origin of Etruscans, first claimed by the classic historians Herodotus and Thucydides, receives strong independent support. As the Latin philosopher Seneca wrote: Asia Etruscos sibi vindicat (Asia claims the Etruscans back).
Project description:BACKGROUND: Bos primigenius, the aurochs, is the wild ancestor of modern cattle breeds and was formerly widespread across Eurasia and northern Africa. After a progressive decline, the species became extinct in 1627. The origin of modern taurine breeds in Europe is debated. Archaeological and early genetic evidence point to a single Near Eastern origin and a subsequent spread during the diffusion of herding and farming. More recent genetic data are instead compatible with local domestication events or at least some level of local introgression from the aurochs. Here we present the analysis of the complete mitochondrial genome of a pre-Neolithic Italian aurochs. RESULTS: In this study, we applied a combined strategy employing both multiplex PCR amplifications and 454 pyrosequencing technology to sequence the complete mitochondrial genome of an 11,450-year-old aurochs specimen from Central Italy. Phylogenetic analysis of the aurochs mtDNA genome supports the conclusions from previous studies of short mtDNA fragments--namely that Italian aurochsen were genetically very similar to modern cattle breeds, but highly divergent from the North-Central European aurochsen. CONCLUSIONS: Complete mitochondrial genome sequences are now available for several modern cattle and two pre-Neolithic mtDNA genomes from very different geographic areas. These data suggest that previously identified sub-groups within the widespread modern cattle mitochondrial T clade are polyphyletic, and they support the hypothesis that modern European breeds have multiple geographic origins.
Project description:Domesticated cattle were one of the cornerstones of European Neolithisation and are thought to have been introduced to Europe from areas of aurochs domestication in the Near East. This is consistent with mitochondrial DNA (mtDNA) data, where a clear separation exists between modern European cattle and ancient specimens of British aurochsen. However, we show that Y chromosome haplotypes of north European cattle breeds are more similar to haplotypes from ancient specimens of European aurochsen, than to contemporary cattle breeds from southern Europe and the Near East. There is a sharp north-south gradient across Europe among modern cattle breeds in the frequencies of two distinct Y chromosome haplotypes; the northern haplotype is found in 20 out of 21 European aurochsen or early domestic cattle dated 9500-1000 BC. This indicates that local hybridization with male aurochsen has left a paternal imprint on the genetic composition of modern central and north European breeds. Surreptitious mating between aurochs bulls and domestic cows may have been hard to avoid, or may have occurred intentionally to improve the breeding stock. Rather than originating from a few geographical areas only, as indicated by mtDNA, our data suggest that the origin of domestic cattle may be far more complex than previously thought.
Project description:BACKGROUND: When domestic taurine cattle diffused from the Fertile Crescent, local wild aurochsen (Bos primigenius) were still numerous. Moreover, aurochsen and introduced cattle often coexisted for millennia, thus providing potential conditions not only for spontaneous interbreeding, but also for pastoralists to create secondary domestication centers involving local aurochs populations. Recent mitochondrial genomes analyses revealed that not all modern taurine mtDNAs belong to the shallow macro-haplogroup T of Near Eastern origin, as demonstrated by the detection of three branches (P, Q and R) radiating prior to the T node in the bovine phylogeny. These uncommon haplogroups represent excellent tools to evaluate if sporadic interbreeding or even additional events of cattle domestication occurred. METHODOLOGY: The survey of the mitochondrial DNA (mtDNA) control-region variation of 1,747 bovine samples (1,128 new and 619 from previous studies) belonging to 37 European breeds allowed the identification of 16 novel non-T mtDNAs, which after complete genome sequencing were confirmed as members of haplogroups Q and R. These mtDNAs were then integrated in a phylogenetic tree encompassing all available P, Q and R complete mtDNA sequences. CONCLUSIONS: Phylogenetic analyses of 28 mitochondrial genomes belonging to haplogroups P (N?=?2), Q (N?=?16) and R (N?=?10) together with an extensive survey of all previously published mtDNA datasets revealed major similarities between haplogroups Q and T. Therefore, Q most likely represents an additional minor lineage domesticated in the Near East together with the founders of the T subhaplogroups. Whereas, haplogroup R is found, at least for the moment, only in Italy and nowhere else, either in modern or ancient samples, thus supporting an origin from European aurochsen. Haplogroup R could have been acquired through sporadic interbreeding of wild and domestic animals, but our data do not rule out the possibility of a local and secondary event of B. primigenius domestication in Italy.
Project description:BACKGROUND: The aurochs (Bos primigenius) was a large bovine that ranged over almost the entirety of the Eurasian continent and North Africa. It is the wild ancestor of the modern cattle (Bos taurus), and went extinct in 1627 probably as a consequence of human hunting and the progressive reduction of its habitat. To investigate in detail the genetic history of this species and to compare the population dynamics in different European areas, we analysed Bos primigenius remains from various sites across Italy. RESULTS: Fourteen samples provided ancient DNA fragments from the mitochondrial hypervariable region. Our data, jointly analysed with previously published sequences, support the view that Italian aurochsen were genetically similar to modern bovine breeds, but very different from northern/central European aurochsen. Bayesian analyses and coalescent simulations indicate that the genetic variation pattern in both Italian and northern/central European aurochsen is compatible with demographic stability after the last glaciation. We provide evidence that signatures of population expansion can erroneously arise in stable aurochsen populations when the different ages of the samples are not taken into account. CONCLUSIONS: Distinct groups of aurochsen probably inhabited Italy and northern/central Europe after the last glaciation, respectively. On the contrary, Italian and Fertile Crescent aurochsen likely shared several mtDNA sequences, now common in modern breeds. We argue that a certain level of genetic homogeneity characterized aurochs populations in Southern Europe and the Middle East, and also that post-glacial recolonization of northern and central Europe advanced, without major demographic expansions, from eastern, and not southern, refugia.
Project description:BACKGROUND:Distinct domestication events, adaptation to different climatic zones, and divergent selection in productive traits have shaped the genomic differences between taurine and indicine cattle. In this study, we assessed the impact of artificial selection and environmental adaptation by comparing whole-genome sequences from European taurine and Asian indicine breeds and from African cattle. Next, we studied the impact of divergent selection by exploiting predicted and experimental functional annotation of the bovine genome. RESULTS:We identified selective sweeps in beef cattle taurine and indicine populations, including a 430-kb selective sweep on indicine cattle chromosome 5 that is located between 47,670,001 and 48,100,000 bp and spans five genes, i.e. HELB, IRAK3, ENSBTAG00000026993, GRIP1 and part of HMGA2. Regions under selection in indicine cattle display significant enrichment for promoters and coding genes. At the nucleotide level, sites that show a strong divergence in allele frequency between European taurine and Asian indicine are enriched for the same functional categories. We identified nine single nucleotide polymorphisms (SNPs) in coding regions that are fixed for different alleles between subspecies, eight of which were located within the DNA helicase B (HELB) gene. By mining information from the 1000 Bull Genomes Project, we found that HELB carries mutations that are specific to indicine cattle but also found in taurine cattle, which are known to have been subject to indicine introgression from breeds, such as N'Dama, Anatolian Red, Marchigiana, Chianina, and Piedmontese. Based on in-house genome sequences, we proved that mutations in HELB segregate independently of the copy number variation HMGA2-CNV, which is located in the same region. CONCLUSIONS:Major genomic sequence differences between Bos taurus and Bos indicus are enriched for promoter and coding regions. We identified a 430-kb selective sweep in Asian indicine cattle located on chromosome 5, which carries SNPs that are fixed in indicine populations and located in the coding sequences of the HELB gene. HELB is involved in the response to DNA damage including exposure to ultra-violet light and is associated with reproductive traits and yearling weight in tropical cattle. Thus, HELB likely contributed to the adaptation of tropical cattle to their harsh environment.
Project description:The Eastern European Grey cattle are regarded as the direct descendants of the aurochs (Bos taurus primigenius). Nowadays in Romania, less than 100 Grey animals are being reared and included in the national gene reserve. We examined the genetic diversity among Romanian Grey, Brown, Spotted and Black and White cattle breeds, with a particular focus on Romanian Grey through the use of (i) 11 bovine specific microsatellite markers on 83 animals and (ii) 638 bp length of mitochondrial DNA (mtDNA) D-loop region sequence data from a total of 81 animals. Both microsatellite and mtDNA analysis revealed a high level of genetic variation in the studied breeds. In Romanian Grey a total of 100 alleles were found, the mean number of observed alleles per locus was 9.091; the average observed heterozygosity was 0.940; the Wright's fixation index (FIS) was negative (-0.189) and indicates that there is no inbreeding and no selection pressure. MtDNA analysis revealed 52 haplotypes with 67 variable sites among the Romanian cattle breeds without any insertion or deletion. Haplotype diversity was 0.980 ± 0.007 and ranged from 0.883 ± 0.056 (Brown) to 0.990 ± 0.028 (Spotted and Black and White). The highest genetic variability of the mtDNA was recorded in the Grey breed, where 18 haplotypes were identified. The most frequent mtDNA D-loop region belonged to T3 haplogroup (80.247%), which was found across all studied breeds, while T2 haplotypes (16.049%) was only found in Grey, Spotted and Black and White genotypes. The T1 haplotypes (3.704%) were found in the Grey and Spotted. The current results contribute to the general knowledge on genetic diversity found in Eastern European cattle breeds and could prove a valuable tool for the conservation efforts of animal genetic resources (FAnGR).
Project description:Cattle domestication from wild aurochsen was among the most important innovations during the Neolithic agricultural revolution. The available genetic and archaeological evidence points to at least two major sites of domestication in India and in the Near East, where zebu and the taurine breeds would have emerged independently. Under this hypothesis, all present-day European breeds would be descended from cattle domesticated in the Near East and subsequently spread during the diffusion of herding and farming lifestyles. We present here previously undescribed genetic evidence in contrast with this view, based on mtDNA sequences from five Italian aurochsen dated between 7,000 and 17,000 years B.P. and >1,000 modern cattle from 51 breeds. Our data are compatible with local domestication events in Europe and support at least some levels of introgression from the aurochs in Italy. The distribution of genetic variation in modern cattle suggest also that different south European breeds were affected by introductions from northern Africa. If so, the European cattle may represent a more variable and valuable genetic resource than previously realized, and previous simple hypotheses regarding the domestication process and the diffusion of selected breeds should be revised.
Project description:<h4>Background</h4>Ancient DNA analysis offers a way to detect changes in populations over time. To date, most studies of ancient cattle have focused on their domestication in prehistory, while only a limited number of studies have analysed later periods. Conversely, the genetic structure of modern cattle populations is well known given the undertaking of several molecular and population genetic studies.<h4>Results</h4>Bones and teeth from ancient cattle populations from the North-East Baltic Sea region dated to the Prehistoric (Late Bronze and Iron Age, 5 samples), Medieval (14), and Post-Medieval (26) periods were investigated by sequencing 667 base pairs (bp) from the mitochondrial DNA (mtDNA) and 155 bp of intron 19 in the Y-chromosomal UTY gene. Comparison of maternal (mtDNA haplotypes) genetic diversity in ancient cattle (45 samples) with modern cattle populations in Europe and Asia (2094 samples) revealed 30 ancient mtDNA haplotypes, 24 of which were shared with modern breeds, while 6 were unique to the ancient samples. Of seven Y-chromosomal sequences determined from ancient samples, six were Y2 and one Y1 haplotype. Combined data including Swedish samples from the same periods (64 samples) was compared with the occurrence of Y-chromosomal haplotypes in modern cattle (1614 samples).<h4>Conclusions</h4>The diversity of haplogroups was highest in the Prehistoric samples, where many haplotypes were unique. The Medieval and Post-Medieval samples also show a high diversity with new haplotypes. Some of these haplotypes have become frequent in modern breeds in the Nordic Countries and North-Western Russia while other haplotypes have remained in only a few local breeds or seem to have been lost. A temporal shift in Y-chromosomal haplotypes from Y2 to Y1 was detected that corresponds with the appearance of new mtDNA haplotypes in the Medieval and Post-Medieval period. This suggests a replacement of the Prehistoric mtDNA and Y chromosomal haplotypes by new types of cattle.