Yonezawa Takahiro, Nishibori Masahide, Yamamoto Yoshio, Sasaki Takeshi, Kudo Kohei, Ogawa Hiroshi, Endo Hideki, Akishinonomiya Fumihito
Faculty of Agriculture, Tokyo University of Agriculture, 1737 Funako, Atsugi city, Kanagawa 243-0034, Japan.
Graduate School of Integrated Sciences for Life, Hiroshima University, Kagamiyama 1-4-4, Higashi-Hiroshima city, Hiroshima 739-8528, Japan.
J Poult Sci. 2022 Oct 25;59(4):316-322. doi: 10.2141/jpsa.0220027.
Japanese native chickens (JNCs) comprise approximately 50 breeds, making Japan a diversity hotspot for native chicken breeds. JNCs were established through the repeated introduction of chickens from foreign countries. Jidori, which is the generic name of JNC breeds whose ancestral morphology resembles that of their wild progenitor (red junglefowls), is generally thought to have propagated from north East Asia (Korea and north China) to ancient Japan. However, mitochondrial haplogroup D, which is abundant in Island Southeast Asia (ISEA) as well as the Pacific but relatively rare in other regions, can be observed in some Jidori breeds (e.g., Tosa-Jidori, Tokuji-Jidori) with high frequency, leading to speculation that chickens from ISEA or the Pacific also contributed genetically to JNCs. To test this hypothesis, we sequenced the mitochondrial genomes of Jidori breeds and conducted phylogeographic analysis. Our results indicate that the JNC Haplogroup D belongs to Sub-haplogroup D2, which is currently only observed in Xinjiang, northwest China, and not to Sub-haplogroup D1, which is widely distributed in the ISEA-Pacific region. The other mitochondrial haplogroups of Jidori examined in this study also showed affinity to those of chickens native to north East Asia. Therefore, our findings support the north East Asian origin hypothesis for Jidori.
日本本土鸡（JNCs）约有50个品种，这使日本成为本土鸡品种的多样性热点地区。JNCs是通过反复引入外国鸡种而形成的。地鸡是JNC品种的统称，其祖先形态与野生祖先（红原鸡）相似，一般认为是从东亚东北部（韩国和中国北方）传播到古代日本的。然而，线粒体单倍群D在东南亚岛屿（ISEA）以及太平洋地区很丰富，但在其他地区相对稀少，在一些地鸡品种（如土佐地鸡、德治地鸡）中可以高频观察到，这引发了一种推测，即来自ISEA或太平洋地区的鸡也在基因上对JNCs有所贡献。为了验证这一假设，我们对一些地鸡品种的线粒体基因组进行了测序，并进行了系统地理学分析。我们的结果表明，JNC单倍群D属于目前仅在中国西北部的新疆被观察到的亚单倍群D2，而不属于广泛分布于ISEA - 太平洋地区的亚单倍群D1。本研究中检测的地鸡的其他线粒体单倍群也显示出与东亚本土鸡的亲缘关系。因此，我们的研究结果支持了地鸡起源于东亚东北部的假设。
