Oldest DNA Ever Discovered in Antarctica is About 1 Million Years Old, Study Shows

The seafloor of Antarctica has been found to contain DNA from some ancient microorganisms, some of which are about 1 million years old.

According to a recent study, the recently discovered DNA was the oldest ever found in seafloor sediments.

As part of a 2019 survey run by the International Ocean Discovery Program in the Scotia Sea located north of mainland Antarctica, scientists unintentionally collected the unexpected genetic samples, identified as sedimentary ancient DNA or sedaDNA, approximately 584 feet beneath the seafloor.

The sedaDNA samples were examined for the first time in the new study.

To determine the precise age of the recovered DNA fragments, the team closely examined damage patterns within them.

The oldest pieces date back about a million years.

Before this discovery, the oldest known sedaDNA was discovered locked away in Arctic permafrost and dated to roughly 650,000 years ago.

NOT a Virus, For Sure!

Linda Armbrecht, a researcher from the University of Tasmania - Institute for Marine and Antarctic Studies in Australia, said that these pieces represent the earliest authenticated marine sedaDNA ever found.

Low temperatures, low oxygen concentrations, and the absence of UV radiation have all contributed to the samples' exceptional state of preservation.

Armbrecht is the lead author of the study.

The oldest sedaDNA is definitely from a eukaryote, which means it originally came from an animal, plant, or fungus and not from a bacteria or virus.

However, scientists are unsure of which species it originated from.

The majority of the DNA samples, however, come from diatoms, a type of phytoplankton that is still present in today's oceans and is the foundation of the majority of marine food webs.

Eukaryotes

Eukaryotes are organisms that have cells with membrane-bound organelles in addition to a nucleus.

Eukaryotic organisms come in a wide variety, including most algae, all animals, plants, and protists.

They are either multicellular or unicellular organisms, and are distinguished from the prokaryotic group of organisms by the existence of internal membranes that divide certain eukaryotic cell components from the rest of the cytoplasm.

Organelles are these membrane-enclosed objects.

In eukaryotes, the genetic material, or DNA, is organized into long molecules known as chromosomes and is housed inside an organelle called the nucleus.

Other organelles found in eukaryotic cells include the Golgi apparatus, which groups and bundles lipids and proteins for transport within the cell; the endoplasmic reticulum, which aids in protein transport; and the mitochondria, which produce energy.

Chloroplasts, additional organelles found in plant cells, are used to capture solar energy.

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Human-Caused Climate Change

The Scotia Sea's sedaDNA record indicates that a likely explosion in diatom abundance occurred around 540,000 years ago, at a time when Earth was going through a natural warming phase.

According to the study's authors, at this time, rapid diatom growth and reproduction were probably fueled by elevated ice loss from the ice sheets of Antarctica, in addition to rising ocean temperatures.

The researchers predicted that similar conditions would likely result from human-caused climate change.

To better understand how ecosystems will change in the future, the team contended that it is critical to learn more about how they changed throughout earlier warming periods.

Armbrecht said that it is urgent to investigate how this polar marine ecosystem has responded to environmental change in the past and present because Antarctica is one of the planet's most vulnerable areas to climate change, Live Science reported.

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