マイクロサテライト ブンセキ ニ モトヅク ニホン ノ エミュー シヨウ シュウダン ニ オケル イデンテキ タヨウド

エミュー（Dromaius novaehollandiae）は食肉，卵およびオイルを生産する新規動物資源となることが期待されている。しかしながら，エミュー産業の歴史は浅く，その生産形質の遺伝的改良はほとんど進んでいない。我々は，日本で最大規模となる北海道網走市のエミュー牧場の個体群を対象としてマイクロサテライト解析に基づく遺伝的多様度を経年的に調査した。検出されたアレルの数（NA）は2013，2014，2015および2016年でそれぞれ4.83，4.17，4.17および7.17であり，ヘテロ接合率（HE/HO）はそれぞれ0.466/0.339，0.426/0.325，0.433/0.384および0.550/0.347であった。近交係数（FIS）は調査したすべての世代において正の値を示し，2016年に孵化した個体では0.369と最も高い値が観察された。Structureプログラムを用いた解析では，本集団は3つのクラスターに分かれ，2016年に孵化した個体群は明らかに他の世代とは異なる遺伝的構成を示した。またアレル共有率に基づく系統樹は5つのクレードを示し，2016年に孵化した個体の約半数は一つのクレードに属した。本研究は，網走市のエミュー集団は遺伝的多様度が低いこと，遺伝的に3－5の異なる系統から構成されること，ならびに2016年に孵化した個体の遺伝的構成が他の世代とは異なることを確認した。The emu (Dromaius novaehollandiae) is predicted to be a new livestock animal for oil, meat and egg production. However, the genetic structure of emu populations in Japanese farms is scarcely known. The aim of this study was to determine the genetic diversity and population structure in the largest emu farm in Japan. We collected feather pulps of emu chicks (N＝131) from 40, 20, 23, and 48 individuals hatched at 2013, 2014, 2015, and 2016, respectively, in the Okhotsk Emu farm in Abashiri, Hokkaido, Japan. Using six microsatellite markers, we investigated the genetic diversity and structure of this farmed emu population. The number of alleles (NA) were 4.83, 4.17, 4.17, and 7.17, in individuals hatched in 2013, 2014, 2015, and 2016, respectively. Expected and observed heterozygosity (HE ; HO, respectively) was 0.466/0.339, 0.426/0.325, 0.433/0.384, and 0.550/0.347, in each year, respectively. A high inbreeding coefficient (FIS) was observed in all tested generations (0.113-0.369). The Structure program and unrooted phylogenetic tree analysis showed that the Abashiri emu population is largely divided into three to five different clades. Our results suggested that the genetic diversity in the Abashiri emu population is low, and that it contains three to five genetic lineages. These data may help guide a more sustainable breeding of emus in Japan

Development of nuclear DNA markers to characterize genetically diverse groups of Misgurnus anguillicaudatus and its closely related species

Repetitive DNA sequences, ManDra and ManBgl, were isolated from the DraI and BglII digests of the genomic DNA of Misgurnus anguillicaudatus, respectively. A primer set of ManDra distinguished two genetically different groups (A and B) of M. anguillicaudatus by specific electrophoretograms. A primer set of ManBgl amplified the DNA of M. anguillicaudatus and M. mizolepis. The individuals of M. anguillicaudatus were divided into two groups depending on the fragment sizes, in which the groups A and B (B-1 and B-2) showed 400 and 460 bp, respectively. M. mizolepis was distinguished by a different pattern (400-, 460-, and 510-bp fragments). PCR-RFLP analyses of recombination activating gene 1 gave a clear difference between A or B-2 (443-bp fragment) and B-1 groups (296- and 147-bp fragments). Clonal lineages and hybrids between B-1 and B-2 groups could be identified by appearance of three fragments (443, 296, and 147 bp). The combined analyses using the above three nuclear markers discriminated among nuclear genomes of genetic groups (A, B-1 and B-2) of M. anguillicaudatus and M. mizolepis. In several localities, natural hybridizations between the group B-1 and B-2 loaches and introgressions of clonal mitochondrial genomes into the group B-1 loaches were detected