Functional extinction of birds drives rapid evolutionary changes in seed size

Functional extinction of birds that feed on large seeds in the Brazilian Atlantic forest is associated with reduction in seed size of a palm species.  Seed size is an important trait for many aspects of a plant’s fitness, however, the size of a seed can constrain it’s dispersal capacity by reducing the number of bird taxa capable of seed dispersal because only large-bodied birds can ingest seeds above a certain size.  The probability of large seeds being dispersed is reduced when large seed feeding birds are extirpated, thereby likely lending selective pressure for reduced seed size and greater dispersal facility in the absence of birds capable of dispersing large seeds.  The authors find reduction of seed size likely occurred within the past 100 years, subsequent to human-driven deforestation and habitat fragmentation. This research suggests broad implications for the current reduction in large vertebrates on the evolutionary trajectories and community composition in many tropical forests.

“No evidence of aquatic humanoids has ever been found…”

In response to a recent deluge of inquiries about the mythical creatures, the National Oceanic and Atmospheric Admistration (NOAA) has attempted to clarify the situation by releasing the following statement: “no evidence of aquatic humanoids has ever been found”.

Aboriginal Australian genome reveals separate human dispersals into Asia

Sequencing the genome of an Aboriginal Australian indicates that Aborigines diverged ~62,000-75,000 years ago from the gene pool shared by all living non-african humans, and represent a separate migration into Asia from the ancestors of modern Asians, which diverged from european ancestors ~25,000-38,000 years ago.   The authors note that their data is consistent with Aboriginal Australians being the direct descendants from the first humans in Australia, dating to ~50,000 years B.P., suggesting that Aboriginal Australians likely have one of the oldest continuous population histories outside sub-Saharan Africa today.

Rotifers dry up and blow away to escape the Red Queen

Anciently Asexual Bdelloid Rotifers Escape Lethal Fungal Parasites by Drying Up and Blowing Away. — Wilson and Sherman explore a mechanism that asexual rotifers may utilize (dessication and aeolian dispersal) to escape the Red Queen model’s problem of coevolved pathogens/parasites in asexual lineages.

Potential new therapeutic target for cancer metastasis

Interactions between cancer stem cells and their niche govern metastatic colonization. —   Malanchi, et al., find that infiltrating tumour cells need to induce stromal periostin (POSTN) expression in the secondary target organ to initiate colonization. POSTN is required for cancer stem cell maintenance, and blocking its function prevents metastasis.  POSTN recruits Wnt ligands and thereby increases Wnt signalling in cancer stem cells at the site of secondary colonization.  The authors hypothesize that the influence on stromal cells by infiltrating tumour cells is an important step in metastatic colonization, and that preventing de novo niche formation may be a novel strategy for the treatment of metastatic disease.

Third cnidarian genome published!

Acropora digitifera genome suggests earlier date for anemone-coral divergence of about 500 million years ago, approximately 260 million years earlier than the emergence of reef-building scleractinian corals in the fossil record.