At Cell Press:
Antarctic krill (Euphausia superba) is Earth’s most abundant wild animal, and its enormous biomass is vital to the Southern Ocean ecosystem. Here, we report a 48.01-Gb chromosome-level Antarctic krill genome, whose large genome size appears to have resulted from inter-genic transposable element expansions. Our assembly reveals the molecular architecture of the Antarctic krill circadian clock and uncovers expanded gene families associated with molting and energy metabolism, providing insights into adaptations to the cold and highly seasonal Antarctic environment. Population-level genome re-sequencing from four geographical sites around the Antarctic continent reveals no clear population structure but highlights natural selection associated with environmental variables. An apparent drastic reduction in krill population size 10 mya and a subsequent rebound 100 thousand years ago coincides with climate change events. Our findings uncover the genomic basis of Antarctic krill adaptations to the Southern Ocean and provide valuable resources for future Antarctic research. – (open access)
So the krill genome is something like a species biography? That’ll be handy for researchers. The human genome is, we are told, only 3.2 billion bp (or 6.4 billion if diploid).
We’ve come a long way from junk DNA.* Now we are reading the library for clues about the history.
Note: The Guiness Book of World Records assigns the largest genome to the Mexican axolotl:
The largest genome (a species’ total genetic material) currently mapped for an animal is that of the axolotl (Ambystoma mexicanum). Also known as the Mexican salamander, this famously neotenic species (able to reproduce while still in the larval state, it frequently never matures) has a 32-gigabase genome, i.e., 32 billion base pairs – the basic units or building blocks of DNA. This is at least 10 times as many base pairs as recorded in the human genome.
Update: In The Mysterious Epigenome: What Lies Beyond DNA, on pages 35-36, James Gills and Tom Woodward point out that the Japanese plant “Paris japonica” hitg 149 gb of DNA, topped only by two amoebas: “Amoeba proteus” at 290 gb and “Polychaos dubium” at 670 gb. Lotta history there maybe.
*Because junk DNA sounded like a slam dunk for Darwinism, as politically powerful theistic evolutionist Francis Collins was quick to point out in The Language of God. (2007). To say nothing of atheist cultural icon Richard Dawkins here, Darwinian evolutionary biologist Jerry Coyne (here), and unidirectional skeptic Michael Shermer (here). Notice how that history is quietly being erased. Otherwise, it would be necessary to acknowledge that what many regarded as a correct prediction from Darwinism is not true.