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Penguins May Find It Genetically Difficult to Survive Climate Change
The rise and fall of earth's temperatures over millions of years drives evolution by favoring those species that are able to adapt to changing conditions. Normally, this is a gradual change that shapes species over thousands or even millions of generations. By studying the fossil record, we can identify what kinds of plants and animals changed the quickest. Then there are penguins. Comparing living and fossil penguin species on the genetic level, it turns out that penguins have the lowest rate of evolutionary change of all bird types. That may be the price of becoming so well adapted to an extreme environment in Antarctica, but it doesn't bode well for the birds' futures. The history of penguin evolution tells us that they lost their ability to fly some 60 million years ago, before the polar ice sheets developed, which hints that they may have become trapped in an environment that became hostile, and they had to adapt or die out. Millions of years later, they are specialists, and their lack of ability to change may be deadly as the earth warms at a rapid pace. Read about the latest discoveries in penguin DNA at ScienceAlert. -via Damn Interesting(Image credit: Ben Tubby) #penguin #evolution #DNA
The Trouble with "De-Extinction" Projects
We've read about projects that intend to bring back extinct species, such as mammoths, thylacines, and quaggas. But so far, there's no Jurassic Park. Can we really bring back a species that is extinct? Projects that attempt to recreate the DNA of extinct creatures are running into problems. DNA is fragile, and doesn't preserve well in nature. Studying the genes of related existing animals is helpful, but no one has been able to find all the necessary genes for an extinct species. Other projects are breeding existing species to select for traits of the extinct version. This is called selective back-breeding. While it may result in creatures that resemble extinct species, it won't be that exact species. There is also the possibility of cloning an extinct species, but that requires relatively recent preserved cells, and has yet to succeed. However, the problems encountered so far are not dissuading scientists from trying. But when they do, recreating their environment will be a problem as well. After all, these species went extinct when they could no longer deal with the earth's changing conditions. Read about the various methods and projects that aim to bring back extinct species at Quanta magazine. -via Real Clear Science#deextinction #extinctspecies #DNA #selectivebackbreeding
Can We Bring the Dodo Back from Extinction?
The dodo is a sad story of how quickly a species can be gone due to human irresponsibility. Discovered at the turn of the 17th century, the flightless bird quickly went extinct after only 100 years as it fell victim to hunting by humans and became prey to dogs, cats, and pigs brought by the explorers. But now, there is hope in the de-extinction of the species, as scientists have finally fully sequenced the species' genome. However, it is not yet published, but one of the people behind the sequencing, Beth Shapiro, says it will be soon.Despite the fully sequenced genome, we might still not see a living dodo soon because birds have intricate reproductive pathways. Editing cells and turning them into actual mammals is easier, Shapiro remarks. In other words, we need a new approach for birds.A potential method could be editing a Nicobar pigeon's DNA. As the dodo and this pigeon are closely related genetically, scientists could edit the pigeon's DNA to include the dodo DNA. But it will probably look a bit different compared to the extinct dodo.(Image Credit: 123rf via NZ Herald)#GenomeMapping #DNA #GeneticEngineering #Dodo #Animals
The World's Largest Bacterium Can Grow up to 2 Centimeters Long
When you think of bacteria, you assume that they can only be seen under a microscope. They are single-cell organisms, after all. But scientists have discovered one that can can grow up to two centimeters (.78 inches) long! Yes, that is still only one cell. Thiomargarita magnifica is not the first known bacteria that can be seen with the naked eye, but it is the biggest so far, ten times bigger than scientists thought possible. But that's not all that makes T. magnifica special.Most bacteria contain DNA free-floating in the cell, while higher orders of life package and protect their DNA in a cell nucleus. But T. magnifica separates its DNA in a sac, separate from a water-filled sac that it uses to take in nutrients. That difference blurs the line between bacteria and other single-cell microbes (prokaryotes) and multi-cellular species (eukaryotes).We may have to redefine classifications due to this new discovery. Read about Thiomargarita magnifica and how it was discovered at Science. #bacteria #Thiomargaritamagnifica #DNA
The World's Oldest Family Tree Sheds Light on Neolithic Culture
An excavation into a 5,700-year-old tomb in Hazleton North, Gloucestershire, UK, has unearthed bones that have been genetically mapped to reveal the kinship relations between those buried there. They are almost all descended from one man who had children with four women. These five parents and their offspring are joined by three more generations of their descendants. It's quite a feat to get a DNA analysis from so many different individuals who died so long ago, and the data on their relationships gives us some intriguing clues into their culture. The tomb is organized into sections headed by each of the four women of the first generation, whose descendants are buried in the same section. There are some individuals who were not related to the single first-generation male, but were the child of one of the four first-generation women. One of the more curious finds is that no adult daughters are found in the tomb. That might indicate that daughters were eventually buried with their husbands' families elsewhere, or they may have been cremated. Read the fascinating findings of the family tree constructed thousands of years after the fact at BBC News. -via Damn Interesting#DNA #family tree #archaeology
Female Salamanders Upend What We Know About Reproduction
A line of salamanders of the Ambystoma genus are all female. They produce all female offspring, and have been doing that for millions of years. Yet their offspring are not clones, even if their mitochondrial DNA is always the same. These salamanders mate with males from other species of the same genus, and incorporate their genetic material into the next generation of females. The scientists who studied this phenomenon call it “kleptogenesis” as it involves stealing genetic material from a different species. The unisex Ambystoma are weirder by far than other animals that are made up of only females. In some other female-only species, the females mate with related species because sperm kickstarts the process, then they reject all the males' DNA. In this salamander, the mother picks and chooses which parts of the male's genome will be incorporated into her female offspring. If she has mated with three males, she can incorporate the genes of one, or two, or three of them into her offspring, plus her own, or possibly delete her own, or use any combination of the reproductive DNA she has available. While this hybridization keeps the gene pool fresh, it does not change their reproductive behavior, not does it ever introduce males into the line. If this sounds complicated, it is. The research paper, with its biology jargon, is even more confusing, but you can read a relatively simple description of just how weird these unisexual salamanders are when it comes to their designer babies at Popular Science. -via Metafilter #salamander #reproduction #DNA #gene #kleptogenesis
Viruses Can Be Villains or Heroes
Most of us are familiar with viruses as the tiny packets of DNA that can infect us and make us sick, and antibiotics can't help. Viruses such as smallpox, hepatitis, rabies, diphtheria, and COVID-19 are often quite deadly. But the world of viruses is much larger than those we've had bad experiences with. Viruses infect animals, plants, funguses, and even bacteria. The viruses, or bacteriophages, that invade bacteria cells keep them at manageable levels, whether in the oceans or in our digestive systems. This is an upside to viruses that equate to "the enemy of my enemy is my friend." Scientists are experimenting with bacteriophages that can attack cancer cells. But viruses have contributed to our ecosystem in other ways. There are two types of virus. Virulent phages are the ones that infect cells, replace their DNA, and use the cell to manufacture more virus. The other type are the temperate phages. These viruses will infect a cell and merge its DNA with that of the cell instead of evicting it. It may lie dormant and then become infectious years down the road. Or it may just create new combinations of DNA. In fact, temperate phages may be the crucial method of inserting genes that change existing life forms. Read how that happens at The Conversation. -via Damn Interesting#virus #phage #bacteriophage #DNA
Geneticists Are Trying to Bring the Wooly Mammoth Back to Life
Bioscience and genetics company Colossal raised a whopping $15 million to fund a project that would bring woolly mammoths back to the Arctic Tundra.The ambitious project involves recreating mammoths and returning them to the wild. Scientists aim to create an elephant-mammoth hybrid by making embryos in the laboratory that would carry mammoth DNA. The goal is to make a cold-resistant elephant that looks and behaves like a mammoth. George Church, professor of genetics at Harvard Medical School and one of the co-founders of Colossal, states that they “want something that is functionally equivalent to the mammoth, that will enjoy its time at -40C, and do all the things that elephants and mammoths do, in particular knocking down trees.”If the project succeeds, scientists hope to have their first set of ‘recreated mammoth’ calves in six years. #WoolyMammoths #Science #DNA #ElephantMammothHybrid #Hybrids Image credit: wikimedia commons; Revive & Restore/ The Guardian
LEGO Idea: DNA Double Helix Discovery
This DNA Double Helix LEGO with 10,000 supporters is under review, which means it’s close to being produced and sold!The designer, LegoDNA, claims that this 3000-pieces and 60cm high LEGO shares many accurate features with the real deal, having 12 base pairs. Plus, there’s mini lab with minifigures of great scientists! In case you’re curious, the DNA code in the model is ATG GAC AAG TGA, which can be used to find the protein it codes for.These include:* Complementary base pairing of the 4 bases (Adenine (red) with Thymine (green), Guanine (blue) with Guanine (yellow)) (In the middle of the strands)* 2 Hydrogen bonds between Adenine-Thymine pair, and 3 Hydrogen bonds between Cytosine-Guanine pair* 2 Helices wrapped around each other* A Phosphate group (yellow) at each base level* A change of 36° every base turn
One More Reason the Neanderthals Couldn't Make It
Neanderthals held on for thousands of years after modern humans migrated out of Africa, and then died out. Our understanding of how that happened changes continuously as new research is done. At first we assumed that modern humans killed them off. Then we found Neanderthal DNA in living humans, and began to think that maybe we just absorbed the smaller Neanderthal population. Or maybe it was a combination of the two. Another possibility has emerged: that male Homo sapiens mating with Neanderthal women sabotaged their ability to produce thriving offspring due to genetic differences. Researchers found the culprit is hemolytic disease of the newborn, which includes Rh factor disease and ABO compatibility. From the research paper: We show that Neanderthal and Denisova were polymorphic for ABO and shared blood group alleles recurrent in modern Sub-Saharan populations. Furthermore, we found ABO-related alleles currently preventing from viral gut infection and Neanderthal RHD and RHCE alleles nowadays associated with a high risk of hemolytic disease of the fetus and newborn. Such a common blood group pattern across time and space is coherent with a Neanderthal population of low genetic diversity exposed to low reproductive success and with their inevitable demise. In other words, the Neanderthal population wasn't large or genetically diverse enough to withstand the influx of incompatible blood types from the more populous modern humans. Read a layman's translation of the research with lots of links at Metafilter. (Image credit: Bacon Cph) #Neanderthal #DNA #bloodtype #hemolyticdisease
Mysterious Iron Age Burial May Hold Remains of Elite Nonbinary Person
When archaeologists unearth a grave site, one of the things they want to determine is the gender of the person who was buried there. A 900-year-old burial in Finland, excavated in 1968, has flummoxed researchers for decades. The remains were dressed as a woman, but given a warrior's burial with a sword. Was this a female warrior, or had the grave originally contained both a man and a woman? A new DNA study may have the answer. As NPR’s Xcaret Nuñez reports, the individual likely had a genetic condition called Klinefelter syndrome. While girls are typically born with two X chromosomes and boys with one X and one Y chromosome, people with Klinefleter syndrome have two X chromosomes and one Y. Generally, those affected have mostly male physical characteristics, but they may also experience low testosterone levels, undescended testes and enlarged breasts. Most are infertile.“If the characteristics of the Klinefelter syndrome [had] been evident on the person, they might not have been considered strictly a female or a male in the early Middle Ages community,” says lead author Ulla Moilanen, an archaeologist at the University of Turku in Finland, in a statement.Considering the grave contained clues that this was a high-status person, the study might give us a new view of Finnish Iron Age culture. Read more at Smithsonian. (Image credit: The Finnish Heritage Agency)#archaeology #DNA #NonBinary #IronAge #KlinefelterSyndrome #MiddleAges #sword
DNA Extracted From 1,600-Year-Old Sheep Leg Found In Salt Mine
Sheep are one of the first animals domesticated by humans, but not much is known about the details of sheep husbandry in ancient civilizations.Now, we have a bit more information on this topic. A team of researchers recently retrieved a well preserved sheep leg from the Chehrabad salt mine in Iran. It's over 1,600 years old but thanks to the salt, there was even still skin and fur present on it and scientists were able to take some of its DNA for their study.Usually, DNA breaks down quickly as enzymes in the cells degrade the strands in a chemical reaction which involves water. The high concentration of salt sequesters the water molecules, thus preventing them from breaking down the DNA strands.So, what did the scientists find out? Genetic analysis showed that the breed of sheep was that of a fat-tailed variety, which lacked the gene for a woolly coat. This breed of sheep was most likely raised for meat or milk, instead of fleece. Research fellow Kevin Daly said, "This study shows us that the people of Sasanian-era Iran may have managed flocks of sheep specialized for meat consumption, suggesting well developed husbandry practices."#sheep #sheepdomestication #fossil #mummy #mummified #saltmine #DNA #archaeology #genetics #domesticationImage: Deutsches Bergbau-Museum Bochum and Zanjan Cultural Heritage Centre, Archaeological Museum of Zanjan
Viruses Have a Novel Genetic Alphabet in Their DNA
Ask any high school biology student how many bases our genetic material DNA has, and you'll get four as the answer: adenine (A), cytosine (C), guanine (G), and thymine (T).But in a series of new studies published in Science, three teams have identified dozens of viruses that has swapped one of the bases in their DNA for a novel one called 2-aminoadenine, later dubbed 'Z'.From Quanta Magazine:The Z base looks like a chemical modification of A; it’s an adenine nucleotide with an extra attachment. But that modest change allows Z to form a triple hydrogen bond with T, which is more stable than the double bond that holds together A-T....since the alterations were “at the deepest level of chemical organization,” [geneticist Philippe Marlière of the University of Evry in France] said, “my instinct told me this is not just an anecdote. This is a profound violation.”#DNA #virus #bacteriophage #biology #syntheticbiology #genetics
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