Lice Genes Show Way for Ancient Human History
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🔬 Wetin Lice Dey Tell Us About Our Ancestors 🔬
From di time wey our ancestors been dey waka from monkey-like primates to bipedal apes, to humans with big brain, one loyal companion don dey with us all through: di human louse, or Pediculus humanus.
As we journey through life, these lice don record everything for their genes. One new study find out say some lice for America na mix of those wey Native Americans carry go there and others wey European colonists bring.
Marina Ascunce, wey be evolutionary geneticist for U.S. Department of Agriculture, talk say, “We humans no dey live for bubble. Lice na part of our lives and history.”
Lice, wey dey live for people head, hold hair shaft, bite scalp, and drink blood, no fit survive away from human body. Dem dey jump from person to person, and if people dey crammed together for dirty conditions, like overcrowded jail, lice fit spread enter clothes and feed on other body parts.
Other mammals and birds get their own lice. Each species of louse get special adaptation to its host, whether na penguin or bat. Dis kind close relationship don dey since ancient times. For Germany, paleontologists find 44-million-year-old louse with feather bits for im belly.
But because lice fossils no plenty, e hard to know their history well. However, their DNA get plenty clues. By analyzing genetic material from lice, scientists fit build their family tree, find out which species relate pass.
David Reed of University of Florida and im colleagues find out say human lice dey closely related to chimpanzee lice and far related to monkey lice. Dis mean say, for like 25 million years, our lice don dey follow us for our evolutionary path.
E no be say lice dey completely loyal sha. Another species, Pthirus pubis (crabs), dey live only for human pubic hair. Crabs no closely relate to head lice. Instead, Dr. Reed and im colleagues find say their closest cousins na lice wey dey live for gorillas. E possible say early human ancestors pick crabs while dem dey sleep for old gorilla nest, or wen dem dey chop gorilla carcass.
In one study, Dr. Reed and im colleagues compare human lice from different parts of di world. Dem look mitochondrial DNA, wey na only female lice pass give their pikin. Dem find say plenty lice belong to one of two lineages. Amazingly, those lineages split from one female louse wey live like one million years ago. Dr. Reed and im colleagues think say dis deep split happen wen humans expand out of Africa. Along with their own lice, dem pick up lice from Neanderthals or some other extinct group of humans.
🌍 Di Geographic Clusters of Lice 🌍
For 2010, Dr. Ascunce join Dr. Reed team and lead effort to collect DNA from different parts of di world.
For di new study, wey dem publish for journal PLOS ONE, Dr. Ascunce and her colleagues analyze DNA from 274 lice wey dem collect from people for 25 places all over di world, like Honduras, France, Rwanda, and Mongolia.
Di DNA show two geographic clusters of lice. One dey for Africa, Asia, and di Americas. For these lice, di researchers find close genetic link between Honduras and Mongolia. Dem suspect say dis kinship na sign say di Asian people wey first spread enter di Americas about 23,000 years ago bring lice with dem.
Di remaining lice form second cluster, wey di researchers find for Europe, and also for United States, Mexico, and Argentina. Dem also find 33 hybrids of di two clusters, 25 of which dey for di Americas.
Dr. Ascunce and her colleagues see for these results di story of modern history: European colonists sail go New World, bring their lice with dem. For di Americas, di second cluster spread and sometimes end up for heads of people wey already get lice from di first cluster.
But if these lice na truly colonial hybrids, Dr. Ascunce and her colleagues dey puzzled why dem no find more. Di rarity of di hybrids might be because of some kind barrier to interbreeding.
E possible say di two clusters of lice don dey isolated from each other for so long say dem gain mutations wey no mix well wen dem come back together.
Dr. Ascunce talk say lice researchers just dey start their work. For di new study, she and her colleagues look just 16 small regions of louse DNA. Di next wave of research go examine di entire louse genome, and she expect say dis new data go bring more insight.
E fit possible, for example, to understand how human lice evolve di ability to move from head to body, and why only body lice dey carry microbes wey fit cause diseases like typhus. And researchers fit pinpoint exactly how our ancestors pick up di lice wey still dey trouble us today.
“The genetic information we dey see for current human lice fit still tell us tins about our human past,” said Dr. Ascunce.
NOW IN BLACK AMERICAN SLANG
🔬 Lice Dropping Knowledge About Our Roots 🔬
So, check this out: From way back when we were more like monkeys to walking upright and getting all smart, we’ve had these little tag-alongs, the human louse, Pediculus humanus. And guess what? These little critters have been keeping a record of all this in their genes. There’s this new study that found some lice in the Americas are like a mix of those that Native Americans had and others that came over with European folks.
Marina Ascunce, a big brain in evolutionary genetics, says, “We ain’t living in no bubble. Lice, they’re part of our story, our history.”
Lice, hanging out on folks’ heads, gripping onto hair, getting their fill of blood, can’t make it without us. They hop from one head to another, especially where folks are all packed in, like in some crowded, dirty spots.
Every kind of bird and mammal got their own lice, all uniquely tuned to their host. This connection goes way back. Scientists even found a 44-million-year-old louse with some feather bits in its stomach over in Germany.
Lice fossils are rare, but their DNA? It’s like a treasure trove. By checking out their genes, scientists can piece together who’s related to who in the louse world.
For instance, research led by David Reed found that our lice are cousins with chimp lice and more like distant relatives to monkey lice. So, for about 25 million years, our lice have been cruising along with us on this evolutionary road trip.
🌍 Lice Mapping the Globe 🌍
Back in 2010, Dr. Ascunce teamed up with Dr. Reed and started gathering lice DNA from all over. Their latest work, dropped in the journal PLOS ONE, took a look at DNA from 274 lice from places like Honduras, France, Rwanda, and Mongolia.
What they found was two main groups of lice. One group was kicking it in Africa, Asia, and the Americas, with a surprising connection between lice from Honduras and Mongolia. This hints that the first folks who trekked into the Americas brought their lice with them some 23,000 years back.
The other group was chilling in Europe, the U.S., Mexico, and Argentina. Plus, they found 33 lice that were like a blend of both groups, mostly in the Americas.
This mix-up of lice tells a story of back in the day when European settlers hit the New World, bringing their lice along. In the Americas, the two types of lice got together and mixed it up a bit.
But these hybrid lice, they’re kinda rare. Dr. Ascunce thinks maybe there was something stopping them from getting too friendly. Maybe they’d been apart so long that their genes weren’t mixing right no more.
Dr. Ascunce says we’re just scratching the surface with lice research. They’ve only looked at bits of lice DNA so far. The next big thing is to check out their whole genetic makeup, which could spill more secrets.
They’re looking to find out how lice made the jump from chilling on heads to other body parts and why it’s only those body lice that carry nasty diseases. And they might even figure out exactly how our ancestors ended up with these pesky roommates.
“The stuff we’re seeing in lice today can still school us about where we came from,” Dr. Ascunce pointed out.
NOW IN ENGLISH
Lice Genes Shed Light on Ancient Human History
🔬 Tracing Human Evolution Through Lice 🔬
Throughout our evolutionary journey from monkey-like primates to bipedal apes and then to humans with large brains, we’ve had a constant companion: Pediculus humanus, commonly known as the human louse. Remarkably, these lice have chronicled our journey in their genes. A recent study revealed that some lice in the Americas are hybrids, originating from those carried by Native Americans and others brought over by European colonists.
“We humans do not exist in isolation,” said Marina Ascunce, an evolutionary geneticist at the U.S. Department of Agriculture and a contributor to the new study. “Lice are intertwined with our lives and our history.”
Lice typically reside on human heads, clinging to hair shafts, piercing the scalp, and consuming blood. They can’t survive away from human bodies, thus transmitting easily in crowded, unsanitary conditions.
Each species of mammal and bird hosts its own lice species, each exquisitely adapted to its particular host. This relationship is ancient, evidenced by a 44-million-year-old louse found in Germany with feather remnants in its gut.
While lice fossils are rare, their DNA offers substantial insights. By analyzing lice genetic material, entomologists can construct their family trees, identifying related species.
For example, research by David Reed of the University of Florida and his team found that human lice are most closely related to chimpanzee lice and more distantly to monkey lice. For roughly 25 million years, our lice have been evolving alongside us.
🌍 The Geographical Spread of Lice 🌍
In 2010, Dr. Ascunce joined Dr. Reed’s team, leading an initiative to collect lice DNA from a more diverse global range. Their new study, published in the journal PLOS ONE, analyzed DNA from 274 lice samples from 25 locations worldwide, including Honduras, France, Rwanda, and Mongolia.
The DNA data uncovered two geographic clusters of lice. One was prevalent in Africa, Asia, and the Americas, where the researchers observed a genetic link between lice from Honduras and Mongolia. This suggests that the first Asian migrants to the Americas brought lice with them about 23,000 years ago.
The second cluster was found in Europe, the United States, Mexico, and Argentina. Additionally, 33 hybrids of these two clusters were identified, with 25 located in the Americas.
These findings paint a picture of modern history: European colonists arriving in the New World brought their lice, leading to the spread and hybridization of lice populations.
The scarcity of these hybrids may indicate some barrier to interbreeding, possibly due to long-term isolation leading to incompatible mutations.
Dr. Ascunce emphasizes that lice research is still in its infancy. The new study examined only 16 small regions of louse DNA. Upcoming research aims to analyze the entire louse genome, promising further revelations.
Future studies might clarify how human lice evolved to move from the head to the body and why only body lice transmit diseases like typhus. Researchers also hope to pinpoint how our ancestors first encountered the lice that continue to affect us.
“The genetic data in current human lice can still reveal aspects of our human past,” Dr. Ascunce noted.
