Defining the Role of Mountains in the Global Carbon Budget

                               Defining the Role of Mountains in the Global Carbon Budget

Scientists working in the mountains of New Zealand report very high rates of soil weathering, contradicting previous studies suggesting mountainous soil weathering has a speed limit. Since the weathering process can pull carbon dioxide from the atmosphere, this find has important implications for scientists’ understanding of mountains as carbon sinks. To shed some light on the matter, Isaac Larsen and colleagues took soil samples from the western Southern Alps of New Zealand, some of the fastest-uplifting mountains in the world. The researchers compared their soil weathering rates against a compilation of worldwide data and found theirs to be the highest anywhere to date. The work of Larsen et al. helps quantify the importance of tectonic activity and erosion as drivers of global weathering fluxes, and thus ultimately as controls on atmospheric carbon dioxide. It also has important ramifications for the currently contentious debate about whether mountains “matter” for global weathering, carbon dioxide cycling, and climate.

Ancient Dog Cancer Hints at First Canine Host

                                       Ancient Dog Cancer Hints at First Canine Host 


Researchers have provided the first whole-genome sequence of a transmissible tumor that originated in a single dog over 10,000 years ago and continues to spread among domestic dogs to this day. Canine transmissible venereal tumor, or CTVT, is one of two known transmissible cancers; it spreads within domestic dog populations by the transfer of living cancer cells, typically during sex. Though these cancer cells have a genome sequence derived from a dog, they are now living on their own in many dog species, as parasitic organisms. Inside the tumor DNA code, however, the genome of their very first host continues to survive. In their investigation, the researchers found almost two million somatic mutations -- over a hundred times more somatic mutations than found in most human tumors. The work of Murchison et al., which reveals the origins, history, and evolution of the world's oldest known cancer cell line, highlights the ability of the mammalian somatic genome to adapt and persist in a new ecological niche (here, the canine host). 


[Image: Dogs genetically most similar to the tumor (top to bottom): Siberian husky; Alaskan Malamute; depiction of the CTVT founder; Shar-pei; dingo; Chow chow; and Akita. CREDIT: The tree is modified from vonHoldt et al. by P. Huey/Science.]

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