#multicellular life

[a-guy-named-ben]

Once upon a time, there was an enormous landmass called Pangea. Millions of years passed. Continents drifted apart. Single-celled life emerged from a biochemical soup. Photosynthesis arrived on the scene, and eventually, the tree of life began branching out. Prokaryotes and eukaryotes pursued different evolutionary paths.

Unfathomably, life began to organize, to become more complex. Multicellular organisms developed, exploited various ecological niches, and evolved. Early hominids descended from the trees, and as endless generations marched onward, one small branch of life became human. Civilizations rose and fell; millions battled, loved, experienced joy and terror.

Today, you sit there reading these words on an electronic screen. Tomorrow, you'll read more words on screens, and so on into the future, until eventually you die somehow.

Life will march on after you're gone. Your boss will hire someone else. Your descendants, if you have any, will gradually forget about you. You, like countless others before you, will be whisked away into the past.

So maybe chill the fuck out a little.

[religion-is-a-mental-illness]

Scientists watch single-cell algae evolve into multicellular life

One of the most important leaps in evolution has been observed in a laboratory, offering a hint of how complicated life began.

Scientists have watched a single-celled organism evolve into a multi-celled one in a laboratory, recreating one of the most important leaps in evolutionary history.

Humans are made up of trillions of different types of cells, but it is unclear how and when life evolved from being a single self-replicating cell to a multi-cellular organism.

Now, in a new paper published in the journal Scientific Reports, a team of scientists from the University of Montana have identified a way in which that evolution may have taken place.

[currentsinbiology]

Fossils may be earliest known multicellular life: study

Fossils accidentally discovered in South Africa are probably the oldest fungi ever found by a margin of 1.2 billion years, rewriting the evolutionary story of these organisms which are neither flora nor fauna, researchers said Monday.

If verified as both fungal and multicellular, the 2.4 billion-year-old microscopic creatures—whose slender filaments are bundled together like brooms—could also be the earliest known specimens of the branch of life to which humans belong, they reported in the journal Nature Ecology & Evolution.

Up to now, the first fossil trace of eukaryotes—the "superkingdom" that includes plants, animals and fungi, but not bacteria—dates to only 1.9 billion years ago.

Stefan Bengtson et al, Fungus-like mycelial fossils in 2.4-billion-year-old vesicular basalt, Nature Ecology & Evolution (2017).  DOI: 10.1038/s41559-017-0141

An X-ray of a fossilised gas bubble containing 2.4- billion-year-old creatures

[existentialistmumbojumbo]

Despite dramatic advances in our understanding of the disease, the evolutionary origin of cancer remains a mystery. Earlier claims that cancer is an entirely man-made disease fuelled by modern lifestyles have been discredited, especially given the recent discovery of tumors in a 3,000-year-old skeleton. But when did this disease start to appear in organisms? A new study, published in Nature Communications, presents evidence to suggest that cancer could be as old as multi-cellular life on Earth. The majority of cancers are caused by faulty genes. More specifically, mutations in two classes of genes, known as proto-oncogenes and tumor suppressor genes, lead to tumor development. While the list of genes associated with cancer is extensive, the origin of these genes was unknown.

[emergencenews]

Researchers Discover New Organism Finding will help scientists understand the origins of multicellular life

Source Newsroom: University of Arkansas, Fayetteville, Arkansas

Released: 9/17/2013 8:00 AM EDT 

Newswise — FAYETTEVILLE, Ark. – Researchers at the University of Arkansas have discovered and characterized a new organism that will help scientists understand the molecular mechanisms and ancestral genetic toolkit that enabled animals and fungi to evolve into diverse, multicellular life forms.

Jeffrey Silberman, a professor of biological sciences, isolated a new unicellular anaerobic eukaryote, and worked with former graduate student Matt Brown and others in the lab of Andrew Roger at Dalhousie University in Halifax, Nova Scotia, Cananda, on the genomics and description of this organism, which they named Pygsuia biforma. Brown, now a biology professor at Mississippi State University, is the lead author of the study, which was published August 28 inProceedings of the Royal Society B (Biology), the top British biological research journal.

“The importance of this finding is that it helps us decipher how multicellularity evolved,” Silberman said. “It demonstrates that some genes and proteins that most people think are specific to being multicellular in animals are already present in their unicellular relatives. It is as if the genetic toolkit for becoming multicellular was assembled and modified bit by bit in the single-cell lineages that share a common ancestry with animals.”

Silberman and Brown study the origins and relationships among single-celled eukaryotes, which have nucleus, amoebae and flagellates, some of which are parasites. Animals, plants and fungi are all eukaryotes; that is, they have complex cells with organelles such as a nucleus and mitochondria. Eukaryotes and humans have more in common than most people realize, Silberman said.

Silberman and Brown perform comparative DNA sequence analyses of a type of eukaryote called protists to help find their particular placement or branch on the tree of life. By isolating formerly unexamined anaerobic protists – a diverse group of unicellular microorganisms – and looking at the independent ways they have formed different types of mitochondria, the researchers hope to reveal essential commonalities among all eukaryotes, perhaps even clues that explain their origin.

Genomic analyses of single cell organisms that are specifically related to multicellular lineages often provide clues to understanding the molecular mechanisms involved in the evolution of multi-cellular life.

To characterize the new organism, which was collected from brackish sediment in Prince Cove in Marstons Mills, Mass., the researchers described the morphology and sequenced the protein-coding genes of the organism to construct a 159-protein matrix for phylogenetic analyses. Phylogenetics is the study of the evolutionary relationships among groups of organisms. The researchers found that the organism resembled two types of a breviate, which is a unicellular eukaryote, but distinguished itself with its conspicuous, long flagella.

Most importantly, the phylogenetic tree established the organism as a distant but unequivocal relative to a “supergroup” of eukaryotes that include fungi and animals. It provides a glimpse of the various components of cell-to-cell adhesion, which is a requirement for multi-cellular organisms. The organism also possesses components of the integrin-mediated adhesion complex, which in animals plays a key role in cell-to-cell signaling and adhesion to the extracellular matrix.

The genus name for Pygsuia biforma is derived from part of the University of Arkansas Razorbacks sports cheer, “Wooo Pig Sooie,” because it has a row of structures resembling the dorsal bristles of razorbacks, which are feral pigs. “Pyg” replaces “pig” as a play on the Latin Pygmae, a mythical race of pygmies, a reference to their small size, and “sui” replaces “sooie” for brevity and a reference to the animal family to which suids, the ancient biological family of pigs, belong. Consequently the genus name also means “little pig” in mock Latin. The species name, biforma, is derived from the presence two distinct cell forms that are observed in the life cycle.

A culture sample of Pygsuia biforma has been submitted to the Smithsonian Institution.

The researchers’ work was partially funded by the Arkansas Biosciences Institute. 

[wildcat2030]

Bacteria have a bad rap as agents of disease, but scientists are increasingly discovering their many benefits, such as maintaining a healthy gut. A new study now suggests that bacteria may also have helped kick off one of the key events in evolution: the leap from one-celled organisms to many-celled organisms, a development that eventually led to all animals, including humans. Published this month in the inaugural edition of the new online journal eLife, the study by University of California, Berkeley, and Harvard Medical School scientists involves choanoflagellates (aka "choanos"), the closest living relatives of animals. These microscopic, one-celled organisms sport a long tail or flagellum, tentacles for grabbing food and are members of the ocean's plankton community. As our closest living relative, choanos offer critical insights into the biology of their last common ancestor with animals, a unicellular or colonial organism that lived and died over 650 million years ago. "Choanoflagellates evolved not long before the origin of animals and may help reveal how animals first evolved," said senior author Nicole King, UC Berkeley associate professor of molecular and cell biology. (via Did bacteria spark evolution of multicellular life?)