Brit-Am Anthropology and DNA Update
(October 18, 2020, 30 Tishrei, 5781)
Contents:
1. Admixture from South Europe Found in Ancient Philistines
2. Different Dwarf Populations Found on the same Islands at Different Times
3. Blue Eyes and Eye Color in General
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1. Admixture from South Europe Found in Ancient Philistines
Ancient DNA sheds light on the genetic origins of early Iron Age Philistines
Michal Feldman1, Daniel M. Master2,3, Raffaela A. Bianco1, Marta Burri1,
Science Advances 03 Jul 2019: Vol. 5, no. 7, eaax0061
Abstract
Extracts:
The ancient Mediterranean port city of Ashkelon, identified as 'Philistine' during the Iron Age, underwent a marked cultural change between the Late Bronze and the early Iron Age. It has been long debated whether this change was driven by a substantial movement of people, possibly linked to a larger migration of the so-called 'Sea Peoples.' Here, we report genome-wide data of 10 Bronze and Iron Age individuals from Ashkelon. We find that the early Iron Age population was genetically distinct due to a European-related admixture. This genetic signal is no longer detectible in the later Iron Age population. Our results support that a migration event occurred during the Bronze to Iron Age transition in Ashkelon but did not leave a long-lasting genetic signature.
Within the history of the Eastern Mediterranean, the end of the Bronze Age and the beginning of the Iron Age were marked by exceptional cultural disarray that followed the demise of prosperous economies and cultures in Greece, Egypt, the Levant, and Anatolia (1). During the 12th century BCE, coincident with these events, substantive cultural changes appeared in the archeological record of Ashkelon, Ashdod, and Ekron, three of the five core cities mentioned as 'Philistine' in the Hebrew bible.. These settlements were distinct from neighboring sites in architectural traditions and material culture... Resemblances between the new cultural traits and 13th century patterns found in the Aegean have led some scholars to explain this so-called 'Philistine phenomenon' by a migration from an Aegean-related source, potentially associated with the 'Sea Peoples,' a population that is thought to have settled in other parts of the coastal Eastern Mediterranean (2, 3). This hypothesis has been challenged by those arguing that this cultural change was driven by a diffusion of knowledge or internal development of ideas (5-8) rather than by a large-scale movement of people. Even for those who do accept the idea of large-scale mobility, the homeland of the new arrivals is disputed with suggested alternatives including Cyprus or Cilicia (4), a mixture of non-Aegean east Mediterranean peoples (8), and mixed heterogeneous maritime groups, akin to pirates (9). Proposed links go as far as northern Italy where depopulation events have been suggested to trigger population movements throughout the Mediterranean (10).
Recent ancient DNA (aDNA) studies have reported a high degree of genetic continuity in the Levant during the late Pleistocene and early Holocene that was followed by increasing population admixtures with Anatolian- and Iranian-related populations at least up to the Middle Bronze Age (11-14).
We find that all three Ashkelon populations derive most of their ancestry from the local Levantine gene pool. The early Iron Age population was distinct in its high genetic affinity to European-derived populations and in the high variation of that affinity, suggesting that a gene flow from a European-related gene pool entered Ashkelon either at the end of the Bronze Age or at the beginning of the Iron Age. Of the available contemporaneous populations, we model the southern European gene pool as the best proxy for this incoming gene flow. Last, we observe that the excess European affinity of the early Iron Age individuals does not persist in the later Iron Age population, suggesting that it had a limited genetic impact on the long-term population structure of the people in Ashkelon.
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2. Different Dwarf Populations Found on the same Islands at Different Times
Modern people's stature evolved separately millennia after hobbits' extinction.
by
KIONA N. SMITH - 8/2/2018, 9:00 PM
https://arstechnica.com/science/2018/08/the-modern-pygmies-of-flores-are-not-related-to-homo-floresiensis/
On the Indonesian island of Flores, less than a mile from the cave where archaeologists discovered the fossil remains of the small-statured hominin Homo floresiensis, there's a village called Rampasasa that is home to a small population of pygmies. 'Pygmy' is the scientific term for a group of people where adult males are less than about 4.7 feet tall but whose bodies have average human proportions. Most of the people living in Rampasasa fit that description.
It would be easy to assume they're related to the other short-statured residents of Flores, and in fact some of the Rampasasans themselves have made that claim in the past. But a new genetic study says that's not the case. These people show no signs of H. floresiensis in their ancestry, but their genomes do show evidence of a relatively recent adaptation toward shorter height. That means that people with short stature evolved twice on the same island, tens of thousands of years apart.
Height is what's called a polygenic trait, meaning that the combined effects of many genes influence your height (environment, lifestyle, and nutrition also play important roles). The same person's genome may include some gene variants, or alleles, associated with increasing height and others associated with decreasing it. Tucci and her colleagues compared the Rampasasan genomes with a list of alleles that have been linked to height in European populations, and they found that those associated with shorter stature tended to be more common in the Flores islanders than in Europeans, which isn't a surprising result.
And those height-related alleles show up with different frequencies in Rampasasans than in neighboring groups of people, a bigger difference than random genetic drift alone could explain.
Tucci and her colleagues say the Rampasasans, height could be an example of insular dwarfism (also called island dwarfism), an evolutionary process in which animals living on an island, or in another limited, isolated environment, gradually evolve smaller body sizes than their ancestors. Some biologists have suggested that insular dwarfism is an adaptation to limited food resources or smaller prey animals. If that's the case for people on Flores today, they're part of a long evolutionary history of dwarfism on Flores. Besides H. floresiensis, the island was once home to stegodon, a now-extinct pygmy relative of modern elephants.
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3. Blue Eyes and Eye Color in General
The truth about blue eyes
BY CAT LAFUENTE/
https://www.thelist.com/160332/the-truth-about-blue-eyes/?utm_campaign=clip
Extracts:
Edmund Custers, a biostatistician, revealed in an article for Owlcation that a whopping 86 percent of the population in Ireland and Scotland have either blue or green eyes. The situation is similar in Iceland, as 87 percent of men and 89 percent of women have one of the two colors. The expert further explained, "Among European Americans, green eyes are most common in people of recent Celtic or Germanic ancestry."
Today, scientists believe there are at least eight � and, more than likely, as many as 16 � genes involved in determining a person's final eye color.
The Daily Beast reported that the 1985 National Longitudinal Survey of Youth reported that more women than men had green eyes.
Three times as many Dutch women than men were revealed to have green eyes.
Ophthalmologist and researcher Hamadi Kallel agrees that people with green eyes do share some similar personality traits. And it's not what Shakespeare thought. IHeartIntelligence.com quotes Kallel as saying that green-eyed people "have an air of mystery and a quiet self-sufficiency. [They are] often unpredictable, but slow to anger." She continued, "They are original, creative and perform well under great pressure."
... researchers discovered that people with dark eyes experienced increased anxiety, sleep disturbance, and higher levels of pain during childbirth. The women with green and blue eyes, on the other hand, ended up experiencing less anxiety and better tolerating the pain associated with childbirth.
Conversely, two brown-eyed parents can also have a blue-eyed child, according to another article published by the museum. Additionally, that phenotype can stay dormant for generations, and later surface when two carriers of the right genes for blue eyes reproduce. And it's not just limited to blue eyes, either, as brown-eyed parents can also have children with green or hazel eyes as well.
.... women with light eyes had an easier time during labor and delivery than women with dark eyes. Additionally, light-eyed women turned out to be less susceptible to anxiety and depression....
people with brown eyes are less at risk of certain kinds of cancers than fair-eyed folks... folks with azure peepers and fair skin are more at risk of type 1 diabetes...
dark-eyed people had a faster reaction time to a single stimulus than their fair-eyed counterparts. That means that melanin may be directly connected to how quickly people respond to the environment around them. .. brown-eyed people are more sensitive to alcohol, they're less likely to ingest alcohol to the point of physical dependence... folks of the brown-eyed persuasion were perceived as more trustworthy than people with lighter colored eyes, notably in populations with a wide variety of eye colors.
The most rare eye colors in the world are gray eyes, red/violet eyes (which are often in people with severe forms of albinism), and eyes with heterochromia (different colored eyes), all clocking in at less than one percent of all people worldwide.
Thanks to the scientists at Copenhagen University, we now know that somewhere between 6,000 to 10,000 years ago, everyone had brown eyes, according to Science Daily. But at some point during that time, a mutation occurred on the OCA2 gene, which controls how much melanin we produce.
The reason that many babies are born with blue eyes that can later change to brown is, once again, due to the way melanin functions in the human body. When a baby is born, melanin hasn't yet been fully deposited into the iris of the child's eye, which results in the iris being blue. But after a certain period, the genetics kick in and melanin production either ramps up, changing the color of the baby's eye, or doesn't, rendering the color of the iris blue for life. It's just one more way that the human body is truly a mystery.
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