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Ancient DNA Reveals Down Syndrome In 5,000-year-old Remains, Study Says. It's A First
An expansive analysis of the DNA from ancient remains has revealed cases of Down syndrome from the past — and potentially an archaeological first.
The new study, published in the journal Nature Communications on Feb. 20, presented the results from nearly 10,000 screenings of ancient remains.
Researchers were searching for the genetic markers of chromosomal mutations, including Down syndrome and a more rare variation known as Edwards syndrome, found on autosomal DNA. They discovered remains of people with "clear genetic evidence" of these conditions were still "buried with care," which is in line with burial practices for other community members.
Down syndrome occurs when a genetic mutation causes two copies of chromosome 21 to form, resulting in physical and developmental changes, the study authors said in a Feb. 20 statement. Edwards syndrome also comes from a genetic mutation, but it causes three copies of chromosome 18 and more severe outcomes than Down syndrome.
First to 'reliably' detect cases"While we expected that people with Down syndrome certainly existed in the past, this is the first time we've been able to reliably detect cases in ancient remains, as they can't be confidently diagnosed by looking at the skeletal remains alone," study author Adam Rohrlach said in the statement.
The research team used a type of statistical analysis, known as the Bayesian approach, to test the autosomal DNA of 9,855 remains spanning millennia across Earth, the study said.
They first used the model to test the 5,000-year-old remains of an infant found in Ireland that was suspected to have Down syndrome, according to the study, and data confirmed the case.
"The statistical model identifies when an individual has approximately 50% too much DNA that comes from one specific chromosome," study author and lead researcher for the Spanish sites, Patxuka de-Miguel-Ibáñez, said.
After running thousands of DNA samples through the model, they found seven remains that had anomalies, the study said.
"We screened DNA extracted from human remains from the Mesolithic, Neolithic, Bronze and Iron Ages all the way up to the mid-1800's," Rohrlach said.
Researchers positively identified six cases of Down syndrome in the ancient remains, and one case of Edwards syndrome, the first identification of its kind, according to the study.
'Buried with care'The first case of Down syndrome, a 6-month-old female, lived between 2898 and 2700 B.C. In a province of Southern Bulgaria, the study said. She was found buried in a "ceramic vessel" under the floor of an Early Bronze Age home.
Another baby girl, between 12 and 16 months old, was found buried in a section of yard belonging to a home on the island of Aegina, Greece, and lived between 1398 and 1221 B.C., the study said. She was found with a necklace of beads in many colors and sizes.
Three other babies, who likely died shortly after birth, were found at an Early Iron Age burial site in Navarra, Spain, and lived between 801 and 400 B.C., the study said. They were buried with "rich grave goods, including bronze rings, a Mediterranean seashell, and surrounded by the complete remains of three sheep and/or goats," researchers said. One infant was found in what appeared to be a decorated fireplace, likely part of a burial ritual.
The last case of Down syndrome was found in a church graveyard in Helsinki, Finland, dating from 1640 to 1790 A.D., researchers said. The remains were discovered in a wooden coffin decorated with bronze pins and flowers.
One case of Edwards syndrome was found in an infant from the Spain site, according to the study.
Researchers noted the burials followed the traditions of their time and the infants were "buried with care.".
"These individuals were buried according to either the standard practices of their time or were in some way treated specially. This indicates that they were acknowledged as members of their community and were not treated differently in death," Rohrlach said.
The skeletal remains alone were unable to prove whether the infants found in Spain survived childbirth, study author Roberto Risch said, but "they were among the infants buried within homes at the settlement or within other important buildings."
"We don't know why this happened, as most people were cremated during this time, but it appears as if they were purposefully choosing these infants for special burials," Risch said.
Researchers said, based on their research, the rate of Down syndrome cases was much lower than what we see today, but this could be attributed to stillbirths, infants and very young children not being buried and preserved as often as adults in ancient times. Stillborn infants also likely had much more fragile skeletons that might not have survived thousands of years of burial, researchers said.
"As the (autosomal) DNA record continues to grow, genetic disorders with extremely low rates of prevalence will be able to be more frequently discovered," researchers said. "Integrated with contextual and anthropological data, they afford a perspective into the way that these disorders were viewed and treated in past communities."
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Scientists Grew A Pair Of Testicles In A Lab — And They Offer New Hope For Male Infertility
This is pretty nuts — researchers at Israel's Bar-Ilan University have grown "laboratory testicles" they hope could eventually ease male infertility, which affects 10% to 15% of American men.
The tiny, artificial organs, produced from cells extracted from mouse testes, are said to resemble the structure and function of natural mouse testicles. The researchers, led by Dr. Nitzan Gonen, are aiming to develop human-like testicles from human stem cells to help treat developmental sex disorders and infertility.
"Fertility clinics are able to identify some of the problems that cause male infertility — a low sperm count or an abnormal structure — but we don't understand fully what causes this, which genome mutations led to the condition, or what went wrong in the testicle's functioning, as a result of which the tubes do not carry the sperm well," Gonen told the Israeli newspaper Haaretz last week.
"Now it will be possible to study these subjects within the system of the model we have produced," she added.
Biologists have already generated organoids — three-dimensional miniature versions of immature organs — that resemble the brain, kidneys and intestines, from stem cells.
The organoids that Gonen's team formed were cultured from immature testicular cells from neonatal mice.
A fluorescent image of a testicular organoid created from mouse embryos and incubated in a dish for 14 days. Cheli Lev / SWNS The tubular structures formed in the dish are visible after 14 days. Cheli Lev / SWNSThe researchers realized the procedure was a success when they identified tubule-like structures and cellular organization mimicking that of in vivo testis.
The artificial mouse testicles functioned well for nine weeks — which is, in theory, enough time for mouse sperm generation and release to occur. That process takes about 34.5 days.
Testicles have two main functions — the production, storage and maturation of sperm cells and the synthesis of testosterone, the primary male sex hormone.
In the study findings, recently published in the International Journal of Biological Sciences, the scientists noted that their organoids showed "signs of entry into meiosis," the process that reduces the number of chromosomes by half to form sperm cells.
Testicular organoids generated from mice pups and incubated in a dish for 21 days are shown. Aviya Stopel / SWNSGonen's vision is to grow testes organoids to help boys with cancer who may not be able to produce functional sperm.
Biopsies would be taken before their treatment commenced, then fertile sperm would be grown in vitro and frozen so they could use it in the future to have children.
Gonen also sees this technology being used in the livestock industry.
"It's true that if science can find a way to control the sex of farm animals and ensure that all the offspring will be only females or only males, the production of the industry will improve twofold," Gonen explained to Haaretz.
"For example, eight females will be born instead of four females and four males — and the animals in the industry will also benefit, because half of them won't be killed, as is done today," she added.
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