East Asian contributions to Dutch traditional and western commercial chickens inferred from mtDNA analysis.

Understanding the complex origin of domesticated populations is of vital importance for understanding, preserving and exploiting breed genetic diversity. Here, we aim to assess Asian contributions to European traditional breeds and western commercial chickens for mitochondrial genetic diversity. To this end, a 365-bp fragment of the chicken mtDNA D-loop region of 16 Dutch fancy breeds (113 individuals) was surveyed, comprising almost the entire breed diversity of The Netherlands. We also sequenced the same fragment for 160 commercial birds representing all important commercial types from multiple commercial companies that together represent more than 50% of the worldwide commercial value. We identified 20 different haplotypes. The haplotypes clustered into five clades. The commonest clade (E-clade) supposedly originates from the Indian subcontinent. In addition, both in commercial chicken and Dutch fancy breeds, many haplotypes were found with a clear East Asian origin. However, the erratic occurrence of many different East Asian mitochondrial clades indicates that there were many independent instances where breeders used imported exotic chickens for enhancing local breeds. Nucleotide diversity and haplotype diversity analyses showed the influence of the introgression of East Asian chicken on genetic diversity. All populations that had haplotypes of multiple origin displayed high inferred diversity, as opposed to most populations that had only a single mitochondrial haplotype signature. Most fancy breeds were found to have a much lower within-population diversity compared to broilers and layers, although this is not the case for mitochondrial estimates in fancy breeds that have multiple origin haplotypes.

Dana N ，Megens HJ ，Crooijmans RP ，Hanotte O ，Mwacharo J ，Groenen MA ，van Arendonk JA ... -  《-》

Maternal genealogical patterns of chicken breeds sampled in Europe.

The aim of this study was to investigate the maternal genealogical pattern of chicken breeds sampled in Europe. Sequence polymorphisms of 1256 chickens of the hypervariable region (D-loop) of mitochondrial DNA (mtDNA) were used. Median-joining networks were constructed to establish evolutionary relationships among mtDNA haplotypes of chickens, which included a wide range of breeds with different origin and history. Chicken breeds which have had their roots in Europe for more than 3000 years were categorized by their founding regions, encompassing Mediterranean type, East European type and Northwest European type. Breeds which were introduced to Europe from Asia since the mid-19th century were classified as Asian type, and breeds based on crossbreeding between Asian breeds and European breeds were classified as Intermediate type. The last group, Game birds, included fighting birds from Asia. The classification of mtDNA haplotypes was based on Liu et al.'s (2006) nomenclature. Haplogroup E was the predominant clade among the European chicken breeds. The results showed, on average, the highest number of haplotypes, highest haplotype diversity, and highest nucleotide diversity for Asian type breeds, followed by Intermediate type chickens. East European and Northwest European breeds had lower haplotype and nucleotide diversity compared to Mediterranean, Intermediate, Game and Asian type breeds. Results of our study support earlier findings that chicken breeds sampled in Europe have their roots in the Indian subcontinent and East Asia. This is consistent with historical and archaeological evidence of chicken migration routes to Europe.

Lyimo CM ，Weigend A ，Msoffe PL ，Hocking PM ，Simianer H ，Weigend S ... -  《-》

Relatedness and diversity of nine Swedish local chicken breeds as indicated by the mtDNA D-loop.

In this study part of the mitochondrial D-loop was sequenced in a total of 40 samples from nine Swedish local chicken breeds. Among our 40 samples we observed 15 segregating sites and seven different haplotypes. The most common haplotype was present in all investigated individuals in five breeds and together with other haplotypes in three breeds. This haplotype is common in domestic chickens and has been found in both local and commercial breeds in many parts of the world. The breed Ölandshöna was most different from the other Swedish breeds with all three individuals sharing a haplotype that differed from the most common haplotype at nine of the 15 segregating sites.

Englund T ，Strömstedt L ，Johansson AM 《HEREDITAS》

Mitochondrial DNA D-loop sequences suggest a Southeast Asian and Indian origin of Zimbabwean village chickens.

This study sought to assess mitochondrial DNA (mtDNA) diversity and phylogeographic structure of chickens from five agro-ecological zones of Zimbabwe. Furthermore, chickens from Zimbabwe were compared with populations from other geographical regions (Malawi, Sudan and Germany) and other management systems (broiler and layer purebred lines). Finally, haplotypes of these animals were aligned to chicken sequences, taken from GenBank, that reflected populations of presumed centres of domestication. A 455-bp fragment of the mtDNA D-loop region was sequenced in 283 chickens of 14 populations. Thirty-two variable sites that defined 34 haplotypes were observed. In Zimbabwean chickens, diversity within ecotypes accounted for 96.8% of the variation, indicating little differentiation between ecotypes. The 34 haplotypes clustered into three clades that corresponded to (i) Zimbabwean and Malawian chickens, (ii) broiler and layer purebred lines and Northwest European chickens, and (iii) a mixture of chickens from Zimbabwe, Sudan, Northwest Europe and the purebred lines. Diversity among clades explained more than 80% of the total variation. Results indicated the existence of two distinct maternal lineages evenly distributed among the five Zimbabwean chicken ecotypes. For one of these lineages, chickens from Zimbabwe and Malawi shared major haplotypes with chicken populations that have a Southeast Asian background. The second maternal lineage, probably from the Indian subcontinent, was common to the five Zimbabwean chicken ecotypes, Sudanese and Northwest European chickens as well as purebred broiler and layer chicken lines. A third maternal lineage excluded Zimbabwean and other African chickens and clustered with haplotypes presumably originating from South China.

Muchadeyi FC ，Eding H ，Simianer H ，Wollny CB ，Groeneveld E ，Weigend S ... -  《-》

Genetic diversity of Jiangsu native chicken breeds assessed with the mitochondrial DNA D-loop region.

1. The objective of this study was to determine the origin and evolution of chickens from 5 native breeds that are traditionally raised in Jiangsu Province. 2. To address this question, the complete mitochondrial DNA D-loop sequence of 149 chickens from 5 native breeds of Jiangsu Province was analysed. 3. Sequence read lengths of the native breeds were 1231 to 1232 bp, with a single-base deletion from the 859 bp site in the 1231 bp haplotype. A total of 33 variable sites that defined 19 haplotypes were identified. The average haplotype diversity and nucleotide diversity were 0.862 ± 0.017 and 0.00591 ± 0.00135. 4. Phylogenetic analysis showed that genetic structure of the mtDNA haplotypes of Jiangsu chickens are distributed across 5 clades (haplogroups): Clades A, B, C, D, and E. However, most of the individuals characterised in this study belonged to clades A and B. 5. The results of this study indicate that Jiangsu chicken populations have relatively low nucleotide and haplotype diversity and likely share 5 common maternal lineages.

Jia XX ，Lu JX ，Tang XJ ，Fan YF ，Huang SH ，Ge QL ，Gao YS ... -  《-》