オオカミイタチとネコに驚くほど共通する染色体、研究で判明（Aardwolves and cats share surprising chromosome similarities, study finds）

2026-09-24

2026-09-23 テキサスA&M大学

テキサスA&M大学の研究チームは、アフリカ原産のアードウルフ（ツチオオカミ）について、初めて詳細な染色体地図（核型）を作成し、近縁のハイエナ類やネコ科動物との比較染色体解析を行った。アードウルフとブチハイエナでは染色体構造がほぼ維持されていたほか、進化的により遠縁なネコとも予想以上に高い染色体構造の類似性が確認された。ネコの19本の染色体のうち12本はアードウルフの単一染色体と対応し、染色体の大規模な再編成が長い進化過程でも比較的少なかったことが示唆された。さらに、核小体形成部位（NOR）やテロメアの位置も調べ、染色体構造の進化的安定性を裏付けた。今回得られた染色体地図は、断片化されたアードウルフのゲノム配列を染色体レベルで再構築する際の基準となり、哺乳類の進化や遺伝的多様性の研究、希少種の遺伝学的研究にも利用できる。

＜関連情報＞

ツチブタ（Proteles cristatus）の包括的な細胞遺伝学的解析とイエネコ（Felis catus）との比較染色体ペインティング Comprehensive cytogenetic analysis of the aardwolf (Proteles cristatus) and comparative chromosome painting with the domestic cat (Felis catus)

Ellie Kolb, Mayra N Mendoza Cerna, Brian W Davis, Roscoe Stanyon, Terje Raudsepp
Journal of Heredity Published:29 January 2026
DOI:https://doi.org/10.1093/jhered/esag008

Abstract

Aardwolf (Proteles cristatus) is one of the four extant hyenas. Up to now, chromosome analysis of the aardwolf is limited to the knowledge that this insectivorous hyena shares the same 2n = 40 diploid chromosome number with the three bone-crushing hyena species. Here we present a detailed conventional banding and molecular cytogenetic characterization of the aardwolf karyotype. A chromosome-by-chromosome comparison with the spotted hyena (Crocuta crocuta) shows extensive conservation of chromosome size, morphology, and banding patters between the two hyenas. Karyotype conservation in hyenas is further supported by cat-aardwolf Zoo-FISH revealing almost identical patterns with previously available cat-spotted hyena Zoo-FISH, as well as extensive conserved synteny between cats and hyenas. Notably, hyena Chr12 and cat E1 share conserved synteny and carry the single nucleolus organizer region in both groups of species. Telomere-FISH in aardwolf and cat revealed only canonical telomeres and no interstitial sites, thus consistent with the overall karyotype conservation. However, there are also differences between aardwolf and spotted hyena Chr15, Chr16, and Chr19 due to heterochromatic additions in the aardwolf. Of these, the metacentric aardwolf Chr16 serves as a genomic feature that distinguishes this species from the spotted hyena in which the homeologous chromosome is acrocentric. In conclusion, improved cytogenetic and molecular characterization of the aardwolf karyotype expands the comparative knowledge about mammalian karyotypes and chromosome evolution, supports karyotypic conservation in feliform carnivores, and facilitates the construction of a high-quality chromosome-level annotated genome assemblies for the aardwolf and other hyenas.