The yellow-throated marten (Martes flavigula) is a flamboyant oddball in the genus Martes, which also includes the sable, pine marten, stone marten, Japanese marten, and American martens. Unlike any other marten species, yellow-throated martens hunt in packs, usually made up of siblings, and are frighteningly good at that: they successfully take down much bigger animals, such as water deer and macaques. In fact, they appear to be much more advanced socially than their loner relatives – while the overall color of their coat is an olive-tinged agouti-to-black gradient, providing good camouflage in lush foliage, some markings almost definitely serve the purpose of biocommunication: the contrasting black head and white chin, bright yellow chest, and long, black tail are amazingly similar to patterns seen in highly social simians, such as squirrel monkeys.
As of now, the yellow-throated marten is listed as LC (Least Concern) by the IUCN due to wide distribution and considerable numbers, as well as its presence in a number of protected territories. However, like most other martens, it prefers large continuous stretches of old-growth primeval forests, and uncontrolled logging and consequent habitat fragmentation and loss are causing an ongoing decline of its numbers in some parts of its range, which stretches from Pakistan in the west to the Russian Far East in the east and the island of Borneo in the south. In the Russian Far East, the yellow throated-marten, locally known as kharza, coexists with another member of the genus - the sable (Martes zibellina), albeit not always peacefully.
The unusual for martens combination of morphological, genetic and behavioral differences has led some researchers to believe that Martes flavigula, together with its sister species, the Nilgiri marten (Martes gwatkinsii) should be assigned a genus of their own. Further genomic research will help to assess whether this suggestion is founded. Moreover, the species as a whole is poorly studied, and there are reasons to believe that some of the isolated patches that make up its range may in fact host distinct subspecies or even separated species.
Today, we present the chromosome-length assembly for the third marten species of this year. All C-scaffolds of the yellow-throated marten were assigned to the corresponding chromosomes via a Zoo-FISH experiment with the stone marten chromosomes used as probes. In contrast to other marten species, Martes flavigula have more chromosomes: 2n=40 instead of 2n=38. (Fig. 1): you can see the chromosome corresponding to chr8 in the stone marten into two chromosomes (chr9 and 19) in the yellow-throated marten in the whole-genome alignment plot below!
We thank Dr. Rogell Powell (North Carolina State University) for funding 10x Genomics linked-read sequencing for the draft assembly and Dr. Klaus Koepfli and Dr. Alexander Graphodatsky for organizing this sequencing and bringing all of the collaborators together. Also we thank Olga Shilo (deputee director), Rosa Solovyova (head of carnivore department) and Svetlana Verkholantseva (veterinarian) from Rostislav Shilo Novosibirsk Zoo (Russia, Novosibirsk) who provided samples for a cell line. Samples were collected postmortem from a 15-year old male individual called Dixi. These cells were used for both DNA extraction for linked read sequencing and for the Hi-C experiment. DNA extraction and Zoo-FISH experiments were performed by Natalia Serdyukova and Dr Violetta Beklemisheva. The initial assembly was performed by Sergei Kliver. Hi-C experiments and scaffolding to chromosomes were done by Dr. Polina Perelman, Ruqayya Khan and Dr. Olga Dudchenko. The genome annotation and a paper describing this research is in progress.