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DNA says you’re related to a Viking, a medieval German Jew or a 1700s enslaved African? What a genetic match really means

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DNA says you're related to a Viking, a medieval German Jew or a 1700s enslaved African? What a genetic match really means

A genetic match to an ancient person doesn't mean you're more related genealogically.
Mark Edward Atkinson/Tetra Images via Getty Images

Shai Carmi, Hebrew University of Jerusalem and Harald Ringbauer, Max Planck Institute for Evolutionary Anthropology

In 2022, we reported the DNA sequences of 33 medieval people buried in a Jewish cemetery in Germany. Not long after we made the data publicly available, people started comparing their own DNA with that of the 14th-century German Jews, finding many “matches.” These medieval individuals had DNA fragments shared with thousands of people who have uploaded their DNA sequence to an online database, the same way you share DNA fragments with your relatives.

But what type of a relationship with a medieval person does a shared DNA fragment imply?

It turns out, not too much that will with your family roots research.

We are population geneticists who work with ancient DNA. We understand how exciting it can be to find a genetic link to particular people who lived many generations ago. But these DNA matches aren't the tight ties you may be imagining. Here's how it works.

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Sequencing DNA from those who lived long ago

Ancient DNA is a new and rapidly growing field, with a Nobel Prize awarded in 2022 to Svante Pääbo for his foundational work.

Using samples taken from skull bones or teeth, aDNA researchers can sequence the DNA of people who lived as far back as 100,000 years ago. More than 10,000 ancient DNA sequences, or genomes, are currently available. These genomes, which from all corners of the world, have dramatically revolutionized scientists' understanding of human origins.

A new trend in ancient DNA is sequencing the genomes of “historical” individuals: those who have lived during the past millennium.

Examples include genomes from Sweden, Norway, Denmark, Iceland, Poland, Southeastern Europe, and London, Cambridge and Norwich in the U.K. Outside Europe, scientists have sequenced historical genomes from East Asia, the Swahili coast, South Africa, the Canary Islands, Lebanon, Machu Picchu, the Caribbean and the San Francisco Bay area. Genomes of enslaved Africans from Delaware, Maryland, South Carolina and St. Helena are also available.

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Some historical genomes belong to named individuals, Ludwig van Beethoven, the family of the last Russian czar, medieval Hungarian royals, the Lakota Sioux leader Sitting Bull and King Richard III of England.

horse-drawn wagon with two black-clad people in front, pulling coffin marked 'Richard III, 1452-1485'
The remains of King Richard III were reinterred in 2015.
Christopher Furlong via Getty Images News

How could you compare your own DNA with that of these historical people?

Several direct-to-consumer genetic testing companies, such as 23andMe, MyHeritage or Ancestry, make reading your own genome sequence simple and affordable. They compare your DNA with that of their other customers. They identify relatives who share with you long, continuous stretches of identical DNA and to you these matches – from the closest to the more distant.

After initial deliberation, 23andMe now lets customers compare their genomes with historical people. Other genetic testing companies don't yet, but passionate genealogists can take matters into their own hands. For example, the service GEDmatch lets users upload their own DNA data, along with published DNA sequences of any historical people. Once uploaded, GEDmatch will identify any user with whom you share genetic material.

two lines representing chromosomes with green, yellow and red bands along their length
A comparison of one chromosome's DNA sequence between a 14th-century German Jew and two living people who uploaded their DNA to GEDmatch. Each thin vertical bar represents one letter in the DNA sequence and is color-coded based on whether it is a match. A shared DNA fragment appears between living person 1 and the medieval person.
GEDMatch

So, what does a genetic match with a medieval person mean for your genealogy?

Surprisingly, very little.

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Where genealogy and genetics diverge

The first thing to understand is how many ancestors you have in each past generation. One generation back, you have two ancestors. Two generations back, that doubles to four. Then eight, and 16. By 30 generations ago, around the 12th century, you have over one ancestors.

Clearly, at this point, your ancestors include most people from your population who lived back then, excluding a small fraction who left no long-term descendants. This includes, if you have European origins, notable people such as Charlemagne or Edward I, but equally also people of every medieval social class. Your family tree reaches each of these ancestors through numerous lines.

a web of red lines getting denser and denser toward the top of the image, with generations marked 0 to 15 running vertically upwards
The red dot at generation 0 represents a present-day person in a simulated population of 100,000 people. Each tiny red dot represents one person, and the red lines connect people to their . Ancestors reached through multiple lines in the family tree are marked in black circles. The number of lines becomes so large so quickly that beyond 15 generations ago, most ancestors are reached by multiple lines.
Graham Coop

Mathematical research demonstrates the surprising fact. In any given population, the number of lines in your family tree that reach any specific medieval person is about the same between you and everyone else who belongs to the same population you do. In other words, everyone alive is equally related, genealogically, to all medieval people from that population.

The next step is to understand how many ancestors you actually inherit DNA from. Surprisingly again, very few.

Despite your millions or more medieval ancestors, you inherit DNA from only a tiny fraction of them. So, we're sorry, you probably didn't inherit any DNA from Charlemagne or Edward I. For example, you have only about 2,000 genetic ancestors from the 12th century. In other words, your DNA sequence is a mosaic of approximately 2,000 “fragments,” each tracing back to a single 12th-century person.

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Who are the medieval people whose DNA you inherited? Each fragment of your DNA descends from a random line up your family tree – father's mother's mother's father and so on – at each generation in the past, selecting at random one of two parents. The more lines in your family tree that reach a certain medieval person, the more likely you are to inherit DNA from that person.

family tree
For someone alive today, the number of genealogical ancestors doubles each generation. But each DNA fragment (colored bars) is inherited through a random, zigzagging path up the family tree, meaning DNA is inherited only from a small fraction of one's ancestors.
Shai Carmi, CC BY-ND

But remember, the number of family lines that reach a medieval person is about the same for all present-day individuals from a given population. Therefore, all individuals inherit DNA from any medieval person with very similar probabilities. So, sharing genetic material with one particular medieval person or another is just a matter of , and everyone is playing the same .

Here's an analogy. Going to a casino and rolling a roulette ball onto 24 does not mean 24 is your special number. Anyone else might have rolled 24 as well. Similarly, sharing a DNA fragment with any one out of your millions of medieval genealogical ancestors does not mean any special relationship – beyond sharing a DNA fragment.

And if you don't have a shared segment, you just didn't get lucky. It doesn't mean you're any less genealogically related to that medieval person than anyone else from your population who does have a shared segment.

As a side note, a “population” is not always well defined, but these arguments hold generally for people with similar origins.

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How to interpret a historical DNA match

Consider again the medieval German Jews. Some present-day Ashkenazi (European) Jews will share DNA with one particular medieval Jew. Some will share with another. Some will share with none. It's a lottery draw. And given that most Ashkenazi Jews today are genealogically related in a very similar way to the medieval German Jews, seeing that shared DNA fragment does not imply any unique genealogical relatedness.

On the other hand, if you're willing to consider more recent ancestors, DNA matches can be informative. The same mathematical models show that the number of family lines reaching a particular historical person living around 200 or 300 years ago will be very different across present-day people. Therefore, a DNA match with an 18th-century person implies a more specific genealogical relationship, one that most other present-day indviduals do not have.

This pattern was demonstrated in a recent 23andMe study. Comparing the genomes of 18th-century enslaved Africans from Maryland to more than 9 million of their customers, 23andMe discovered over 41,000 living relatives, including a few nearly direct descendants.

3D models of enslaved African Americans: one a teenage boy, one a woman in her 30s
Facial reconstructions based on skeletal remains of enslaved African Americans who worked at Catoctin Furnace in Maryland, where scientists have also sequenced ancient DNA.
Katherine Frey/The Washington Post via Getty Images

How far back in time does a DNA match still have genealogical meaning? For example, are DNA matches informative in the period between the late Middle Ages and the 17th century? We don't know yet. Future research will be needed to clarify this question, as well as deviations from the simple model of a single, freely mixing population.

In the meantime, as scientists rapidly accumulate more and more historical genome sequences, keep the quirky behavior of human genealogies in mind when interpreting a DNA match.The Conversation

Shai Carmi, Associate Professor of Population and Statistical Genetics, Hebrew University of Jerusalem and Harald Ringbauer, Group Leader, Department of Archaeogenetics, Max Planck Institute for Evolutionary Anthropology

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This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Under the influence and under arrest − what happens if you’re drunk in the interrogation room?

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theconversation.com – Jacqueline R. Evans, Associate Professor of Psychology, Florida International – 2024-04-26 07:28:33

In the U.S., if you waive your Miranda rights, you'll be interrogated – whether you're drunk or sober.

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Jacqueline R. Evans, Florida International University

Imagine it's Friday night. You're enjoying happy hour with friends after a long week. You're relaxed, indulged in several of your preferred adult beverages. Now imagine that as you the bar, a officer approaches. You're under arrest.

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Flash forward to the police station. The officer takes you to a cramped room and reads you your Miranda rights: You have the right to remain silent, to an attorney, and all the rest. Let's say you waive those rightsmost people do – and the officer questions you for several hours.

While under the influence, would you understand your Miranda rights and appreciate the consequences of choosing to invoke or waive them? Would the statements you made during questioning be more or less reliable than how you'd respond sober? Would a jury take what the drunken you said seriously? These are the questions that legal psychologists like me and my colleagues seek to address in our research.

Suspects get similar treatment, drunk or not

When we've surveyed police, they revealed it's common to question intoxicated suspects and that they tend to use the same interrogation techniques with drunken suspects that they normally use. Surveys of community members about their experience with interrogation confirm that questioning drunken suspects is common. In fact, sometimes police even interrogate drunken juveniles.

Of course, police in the U.S. cannot legally question anyone in custody unless that person has waived their Miranda rights and chosen to to the investigator. It's a common misperception that drunken people cannot legally waive their Miranda rights and that statements given while intoxicated cannot be used against them in court. But the reality is that from a legal perspective the police can Mirandize you while you're under the influence, interrogate you, and use your statements against you.

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arrow upwards with text describing expected impairments at increasing BAC levels

Level of impairment rises along with how much you've had to drink.

NIH National Institute on Alcohol Abuse and Alcoholism, CC BY

Consider the case of Travis Jewell. When he was for fleeing a police officer in his truck, his blood alcohol level was .29, more than three times the legal limit of .08 in the U.S. The interrogator reported Jewell was slurring words and struggling to stand. Nonetheless, the court accepted his Miranda waiver, making Jewell's statements admissible during trial.

While Miranda waivers from intoxicated people may be legally valid, research from my lab suggests that when with sober individuals, someone under the influence of or alcohol – even at low levels of intoxication – may be less able to comprehend their rights.

Testing how drunken ‘suspects' behave

Critically, researchers know almost nothing about how intoxicated people behave during interrogation.

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To address this need, my colleagues and I brought university student volunteers into the lab, where we have safeguards in place to minimize health risks. We had some of our participants drink enough vodka to reach a breath alcohol level of .08%, a level consistent with the legal driving limit in the U.S.

Then we set the participants up to be guilty or innocent of cheating, and interrogated each of them about potential academic misconduct. We were interested in whether, impaired or sober, they said anything incriminating or suspicious during questioning.

About two-thirds of sober participants said something suggestive of guilt, while even more intoxicated participants did. The difference in suspicious statements between the groups was not statistically significant, but our findings do indicate that intoxicated people – just like the rest of the public – are at a high risk of self-incrimination. And remember, in our study, half of the participants were innocent of the infraction they were being questioned about.

man in striped clothes sits across table from woman in suit jacket

Standard legal advice is to keep your mouth shut until you are able to meet with a lawyer.

AP Photo/Steve Helber

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Suspicious remarks can have immediate consequences during interrogation. When a says something suggestive of guilt, it tends to increase an interrogator's belief that they're guilty. When interrogators have a stronger belief in guilt, they then tend to be more accusatory, an approach associated with false confessions.

Intoxicated suspects – guilty or innocent – are very likely to make a guilt-suggestive statement, which in turn is likely to invite more coercive interrogation approaches. This could potentially explain our recent real-world findings in Sweden that police interrogators used more confrontational techniques with intoxicated suspects than with sober suspects.

On a positive note, our work has also shown that potential jurors seem to recognize that intoxication may to less reliable statements during interrogation. They tend to give less weight to a confession from an intoxicated suspect than from a sober suspect. While that may sound reassuring, should you find yourself in that cramped interrogation room, sober or intoxicated, exercise your rights and ask for an attorney.The Conversation

Jacqueline R. Evans, Associate Professor of Psychology, Florida International University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Cybersecurity researchers spotlight a new ransomware threat – be careful where you upload files

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theconversation.com – Selcuk Uluagac, Professor of Computing and Information Science, Florida International – 2024-04-26 07:28:18

Avoiding iffy downloads is no longer enough to ensure this doesn't happen.

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Selcuk Uluagac, Florida International University

You probably know better than to click on links that download unknown files onto your computer. It turns out that uploading files can get you into trouble, too.

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Today's web browsers are much more powerful than earlier generations of browsers. They're able to manipulate data within both the browser and the computer's local file system. Users can send and email, listen to music or watch a movie within a browser with the click of a button.

Unfortunately, these capabilities also mean that hackers can find clever ways to abuse the browsers to trick you into letting ransomware lock up your files when you think that you're simply doing your usual tasks online.

I'm a computer scientist who studies cybersecurity. My colleagues and I have shown how hackers can gain access to your computer's files via the File System Access Application Programming Interface (API), which enables web applications in modern browsers to interact with the users' local file .

The threat applies to Google's Chrome and Microsoft's Edge browsers but not Apple's Safari or Mozilla's Firefox. Chrome accounts for 65% of browsers used, and Edge accounts for 5%. To the best of my knowledge, there have been no reports of hackers using this method so far.

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My colleagues, who include a Google security researcher, and I have communicated with the developers responsible for the File System Access API, and they have expressed for our work and interest in our approaches to defending against this kind of attack. We also filed a security report to Microsoft but have not heard from them.

Double-edged sword

Today's browsers are almost operating systems unto themselves. They can run software programs and encrypt files. These capabilities, combined with the browser's access to the host computer's files – including ones in the cloud, shared folders and external drives – via the File System Access API creates a new opportunity for ransomware.

Imagine you want to edit photos on a benign-looking free online editing tool. When you upload the photos for editing, any hackers who control the malicious editing tool can access the files on your computer via your browser. The hackers would gain access to the folder you are uploading from and all subfolders. Then the hackers could encrypt the files in your file system and demand a ransom payment to decrypt them.

Today's web browsers are more powerful – and in some ways more vulnerable – than their predecessors.

Ransomware is a growing problem. Attacks have hit individuals as well as , including Fortune 500 companies, , cloud service providers, cruise operators, threat-monitoring services, chip manufacturers, governments, medical centers and hospitals, insurance companies, schools, universities and even departments. In 2023, organizations paid more than US$1.1 billion in ransomware payments to attackers, and 19 ransomware attacks targeted organizations every second.

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It is no wonder ransomware is the No. 1 arms race today between hackers and security specialists. Traditional ransomware runs on your computer after hackers have tricked you into downloading it.

New defenses for a new threat

A team of researchers I at the Cyber-Physical Systems Security Lab at Florida International University, including postdoctoral researcher Abbas Acar and Ph.D. candidate Harun Oz, in collaboration with Google Senior Research Scientist Güliz Seray Tuncay, have been investigating this new type of potential ransomware for the past two years. Specifically, we have been exploring how powerful modern web browsers have become and how they can be weaponized by hackers to create novel forms of ransomware.

In our paper, RøB: Ransomware over Modern Web Browsers, which was presented at the USENIX Security Symposium in August 2023, we showed how this emerging ransomware strain is easy to design and how damaging it can be. In particular, we designed and implemented the first browser-based ransomware called RøB and analyzed its use with browsers running on three different major operating systems – Windows, Linux and MacOS – five cloud providers and five antivirus products.

Our evaluations showed that RøB is capable of encrypting numerous types of files. Because RøB runs within the browser, there are no malicious payloads for a traditional antivirus program to catch. This means existing ransomware detection systems face several issues against this powerful browser-based ransomware.

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We proposed three different defense approaches to mitigate this new ransomware type. These approaches operate at different levels – browser, file system and user – and complement one another.

The first approach temporarily halts a web application – a program that runs in the browser – in order to detect encrypted user files. The second approach monitors the activity of the web application on the user's computer to identify ransomware-like patterns. The third approach introduces a new permission dialog box to inform users about the risks and implications associated with allowing web applications to access their computer's file system.

When it to protecting your computer, be careful about where you upload as well as download files. Your uploads could be giving hackers an “in” to your computer.The Conversation

Selcuk Uluagac, Professor of Computing and Information Science, Florida International University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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How bird flu virus fragments get into milk sold in stores, and what the spread of H5N1 in cows means for the dairy industry and milk drinkers

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theconversation.com – Noelia Silva del Rio, Associate Specialist in Cooperative Extension, Production Medicine and Food Safety, of California, Davis – 2024-04-25 14:04:50

Cows typically get over avian flu in a of weeks, but it's an economic blow for farms.

AP Photo/Charlie Litchfield

Noelia Silva del Rio, University of California, Davis; Richard V. Pereira, University of California, Davis; Robert B. Moeller, University of California, Davis; Terry W. Lehenbauer, University of California, Davis, and Todd Cornish, University of California, Davis

The discovery of viral fragments of avian flu virus in milk sold in U.S. stores suggests that the H5N1 virus may be more widespread in U.S. dairy cattle than previously realized.

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The Food and Drug Administration was quick to stress on April 24, 2024, that it believes the commercial milk supply is safe. However, highly pathogenic avian influenza virus can make cows sick, and the flu virus's presence in herds in several states and now new federal restrictions on the movement of dairy cows between states are putting economic pressure on farmers.

Five experts in infectious diseases in cattle from the University of California, Davis – Noelia Silva del Rio, Terry Lehenbauer, Richard Pereira, Robert Moeller and Todd Cornish – explain what the test results mean, how bird flu can spread to cattle and the impact on the industry.

What are viral fragments of avian flu, and can they pose risks to people?

It's crucial to understand that the presence of viral fragments of H5N1 doesn't indicate the presence of intact virus particles that could cause disease.

The commercial milk supply maintains safety through two critical measures:

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  • First, milk sourced from sick animals is promptly diverted or disposed of, ensuring it does not enter the food chain.

  • Second, all milk at grocery stores is heat treated to reduce pathogen load to safe levels, mainly by pasteurization. Pasteurization has been shown to effectively inactivate H5N1 in eggs, and that occurs at a lower temperature than is used for milk.

The viral fragments were detected using quantitative polymerase chain reaction testing, which is known for its exceptional sensitivity in detecting even trace amounts of viral genetic material. These fragments are only evidence that the virus was present in the milk. They aren't evidence that the virus is biologically active.

To evaluate whether the presence of the viral fragments corresponds to a virus with the capacity to replicate and cause disease, a different testing approach is necessary. Tests such as embryonated egg viability studies allow scientists to assess the virus's ability to replicate by injecting a sample into an embryonated chicken egg. That type of testing is underway.

On April 24, 2024, the FDA said it had found no reason to change its assessment that the U.S. milk supply is safe. The agency does strongly advise against consuming raw milk and products derived from it because of its inherent risks of contamination with harmful pathogens, avian flu viruses.

How does an avian flu virus get into cow's milk?

Currently, cows confirmed to have H5N1 have different symptoms than the typical flu-like symptoms observed in birds.

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Abnormal milk and mastitis, an inflammatory response to infection, are common. While there is speculation that other bodily secretions, such as saliva, respiratory fluids, urine or feces, may also harbor the virus, that has yet to be confirmed.

The legs of a cow showing a milking device attached to the udder and tubes for the milk to flow.

Milking equipment can help viruses spread.

Loic Venance/AFP via Getty Images

How waterfowl or other birds transmitted H5N1 to cattle is still under investigation. In 2015, an outbreak of highly pathogenic avian influenza in commercial poultry farms reached its peak in April and May, the same time birds migrated north. Birds can shed the virus through their oral, nasal, urine and fecal secretions. So the virus could potentially be transmitted through direct contact, ingesting contaminated feed or water, or inhaling the virus.

Infected dairy cows can shed the virus in milk, and they likely can transmit it to other cows, but that still needs to be proven.

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Contagious pathogens that cause mastitis can be transmitted through milking equipment or contaminated milker's gloves. Ongoing research will help determine whether this is also a potential transmission route for H5N1, and if so, what makes the virus thrive on mammary tissue.

If H5N1 is found to be widespread in milk, what risks can that pose for the dairy industry?

For the dairy industry, infection of cattle with H5N1 avian influenza virus creates challenges at two levels.

The overriding concern is always for the safety and healthfulness of milk and dairy products.

Existing and federal regulations and industry practices require sick cows or cows with abnormal milk to be segregated so that their milk does not enter the food supply. Proper pasteurization should kill the virus so that it cannot cause infection.

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The American Association of Bovine Practitioners has also developed biosecurity guidelines for H5N1, focusing on key practices. These include minimizing wild birds' contact with cattle and their environment, managing the movement of cattle between farms, isolating affected animals, avoiding feeding unpasteurized (raw) colostrum or milk to calves and other mammals, and ensuring the use of protective personal equipment for animal caretakers.

The other major concern is for the of the dairy herd and the people who take care of the dairy cattle. A farm worker who handled dairy cows contracted H5N1 in in March 2024, but such cases are rare.

No vaccines or specific therapies are available for avian influenza infections in dairy cattle. But good sanitation and biosecurity practices for both people and cows will help to reduce risk of exposure and spread of the avian influenza virus among dairy cattle.

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For cows that get the virus, providing supportive care, including fluids and fever reducers as needed, can help them get through the illness, which can also cause loss of appetite and affect their milk production.

Dairy farms facing an outbreak will have economic losses from caring for sick animals and the temporary reduction in milk sales. Approximately 5% to 20% of the animals in the affected herds have become ill, according to early estimates. Affected animals typically recover within 10 to 20 days.

At least 21 states have restricted importing dairy cattle to prevent the virus's spread, and the federal announced it will require that lactating dairy cattle be tested before they can be moved between states starting April 29, 2024. While the overall impact on U.S. milk production is projected to be minor on an annual basis, it could to short-lived supply disruptions.

How worried should people be about avian flu?

The federal government's monitoring and food safety measures, along with pasteurization, provide important safeguards to protect the public from potential exposure to avian influenza virus through the food chain.

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Drinking raw milk, however, does represent a risk for exposure to multiple diseases, including H5N1. This is why the FDA and Centers for Disease Control and Prevention strongly recommend drinking only pasteurized milk and dairy products.The Conversation

Noelia Silva del Rio, Associate Specialist in Cooperative Extension, Production Medicine and Food Safety, University of California, Davis; Richard V. Pereira, Associate Professor of Veterinary Medicine and Associate Agronomist, University of California, Davis; Robert B. Moeller, Professor of Veterinary Medicine, University of California, Davis; Terry W. Lehenbauer, Professor of Veterinary Medicine, University of California, Davis, and Todd Cornish, Professor of Veterinary Medicine, University of California, Davis

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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