Mono Lake in the Eastern Sierra Nevada is known for its towering tufa formations, abundant brine shrimp and black clouds of alkali flies uniquely adapted to the salty, arsenic- and cyanide-laced water.
University of California, Berkeley, researchers have now found another unusual creature lurking in the lake’s briny shallows — one that could tell scientists about the origin of animals more than 650 million years ago.
The organism is a choanoflagellate, a microscopic, single-celled form of life that can divide and develop into multicellular colonies in a way that’s similar to how animal embryos form. It’s not a type of animal, however, but a member of a sister group to all animals. And as animals’ closest living relative, the choanoflagellate is a crucial model for the leap from one-celled to multicellular life.
Surprisingly, it harbors its own microbiome, making it the first choanoflagellate known to establish a stable physical relationship with bacteria, instead of solely eating them. As such, it’s one of the simplest organisms known to have a microbiome.
“Very little is known about choanoflagellates, and there are interesting biological phenomena that we can only gain insight into if we understand their ecology,” said Nicole King, a UC Berkeley professor of molecular and cell biology and a Howard Hughes Medical Institute (HHMI) investigator who studies choanoflagellates as a model for what early life was like in ancient oceans.