- 著者
- Hiroyuki NISHIMURA Nobuaki NAKAMUTA Yoshio YAMAMOTO
- 出版者
- The Ornithological Society of Japan
- 雑誌
- ORNITHOLOGICAL SCIENCE (ISSN:13470558)
- 巻号頁・発行日
- vol.22, no.1, pp.35-44, 2023 (Released:2023-01-26)
- 参考文献数
- 54
In this study we investigated the eye morphology and retinal topography of two owl species in relation to their visual environment. Although Short-eared Owl Asio flammeus is larger and weighs more than Japanese Scops Owl Otus semitorques, its eye dimensions (weight, corneal diameter, and axial length) are all smaller than the scops owl's. Owl retinas were examined in Nissl-stained whole-mount preparations. The total number of retinal ganglion cells (RGCs) was greater in the Japanese Scops Owl (4,703.0×103 cells) than in the Short-eared Owl (2,346.8×103 cells). The eye morphology of, and the number of RGCs in the Japanese Scops Owl indicate that it is more adapted to a nocturnal habit. An area of high-density RGCs was horizontally distributed in the temporal retina of the Short-eared Owl, with a peak density of 17.4×103 cells/mm2. In the Japanese Scops Owl's temporal retina, there was an oval-shaped arrangement with a peak density of 23.1×103 cells/mm2. These distributions indicate that whereas Short-eared Owl is adapted to open habitats, Japanese Scops Owl is adapted to enclosed habitats. The RGCs of both species were classified into three categories (small, medium, and large) based on the size and appearance of somas. In both species, medium-sized cells predominated, and the proportion of large-sized cells was smallest. The distribution and high-density areas differed among these groups, suggesting adaptation to the visual environment. The high-density areas of these groups cover the nasal visual fields, which include the overlap for binocular vision.
- 著者
- Takahiro Yonezawa Masahide Nishibori Yoshio Yamamoto Takeshi Sasaki Kohei Kudo Hiroshi Ogawa Hideki Endo Fumihito Akishinonomiya
- 出版者
- Japan Poultry Science Association
- 雑誌
- The Journal of Poultry Science (ISSN:13467395)
- 巻号頁・発行日
- vol.59, no.4, pp.316-322, 2022 (Released:2022-10-25)
- 参考文献数
- 34
- 被引用文献数
- 2
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.
- 著者
- Takahiro Yonezawa Masahide Nishibori Yoshio Yamamoto Takeshi Sasaki Kohei Kudo Hiroshi Ogawa Hideki Endo Fumihito Akishinonomiya
- 出版者
- Japan Poultry Science Association
- 雑誌
- The Journal of Poultry Science (ISSN:13467395)
- 巻号頁・発行日
- pp.0220027, (Released:2022-06-25)
- 被引用文献数
- 2
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.