No laughing matter

The spotted hyena (Crocuta crocuta) aka the laughing hyena is a hyena species native to Sub-Saharan Africa. It is, in fact, the most common large carnivore in Africa [1].

Spotted hyenas are very unusual animals, and there are a lot of mind-blowing facts associated with the species. Unusually for a mammal, the female spotted hyena is considerably larger than the male [1]. Spotted hyenas live in large matriarchal communities. (Cinemaphiles may recall that the spotted hyenas in the film ‘The Lion King’ are led by a female named Shenzi.) Their societies are extremely complex and bear close resemblance to those of baboons and macaques [2]. Evolutionary anthropologists demonstrated that spotted hyenas outperform chimps in at least some cooperative problem-solving tests [3]. Spotted hyenas also have a very unusual reproductive anatomy, making both mating and giving birth extremely difficult. Despite this, their cubs are the largest carnivoran young relative to their mothers' weight [1].

To help understand the biology and evolutionary history of this unique animal, today we release the chromosome-length genome assembly for the spotted hyena, here. The assembly was done following the $1K-model, see (Dudchenko et al., 2018) for details. Samples from two different animals were used for this genome assembly, with both samples donated to us by SeaWorld.

Hyenas belong to the Feliformia suborder (cat relatives), and are cousins to mongooses. See below how the genome of the spotted hyena compares to that of the meerkat (a mongoose in the DNA Zoo collection) and the domestic cat (from Pontius et al., 2007) genome assemblies.

It is interesting to note that while meerkats are more closely related to hyenas (30 MY to common ancestor) than to cats (40 MY to common ancestor), karyotypically they seem to resemble cats much more than they do hyenas (compare the whole-genome alignments between the meerkat and the hyena and the meerkat and the cat, also shown below). We will know more about the evolution of the hyena karyotype once we have a chance to assemble other hyena species, so if you have access to any relevant samples, please reach out!

Whole-genome alignments between the chromosome-length genomes of the spotted hyena (Crocuta_crocuta_HiC), the meerkat (meerkat_22Aug2017_6uvM2_HiC, from DNA Zoo collection) and the domestic cat (Felis_catus_9.0, Pontius et al., 2007)

Whole-genome alignments between the meerkat (meerkat_22Aug2017_6uvM2_HiC) and domestic cat (Felis_catus_9.0). Notice how this plot looks ‘cleaner’ than the one above for the whole-genome alignment between the meerkat and the hyena, indicating a higher degree of conservation at the karyotype level.

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