My grandmother is Italian. Why not my Italian gene?
Maybe you found a tool kit to find your ancestors during the holidays. You have sent out the saliva samples that you have collected in embarrassment, and now you are waiting for your results. If your experience is the same as mine and my mother’s, you may find surprise – not a dramatic “birth change”, but the results are quite different from what you expected.
My mother, Carmen Grayson, taught for 45 years of high school and college history, and retired from Hampton university in the late 1990s. But retired history professors will never retire, so she has been studying her family’s migrations, through paper records and current DNA tests. Her father was French Canadian, and her mother (my eponymous Gisella D ‘appollonia) was born by Italian parents who moved to Canada ten years before their grandmother was born in 1909.
Last fall, we sent a DNA test from Helix, our partner in national geographic. Mom’s score: 31 percent from Italy and southern Europe. This is because of her Italian mother. But my spiral did not even have the “Italian and southern” category. How can I have 50 percent of my mom’s DNA, no Italy? We look very much like, she says we were born with very little chance to switch.
We decided to get a second opinion and send it to another company, 23andMe. We were equally surprised when we opened our results together. This time, I have at least one southern European class. But when mom came back, it was 25% of southern Europe, and I only had 6%. Italy? Mom has my 1.6 11.3%. So maybe there’s nothing wrong with the first test. But how can I have an Italian grandmother who has almost no Italian genes?
To answer this question, my mother and I drove to visited the Johns Hopkins university school of medicine in Baltimore and bloomberg school of public health, Allah Ms. Wen da chakra, Ph.D., his career is in the study of genetics and human health.
When we showed him the results, he told us, “it’s amazing. “But these methods may still have the wrong limitations.”
The science of analyzing a person’s genome is good, says Chakravarti. But the way companies analyze these genes leaves plenty of room for explanation. So, he says, these tests “are the most accurate at the level of continental origin, and as you get higher and higher resolution, they become less and less accurate.
As far as I am concerned, the result is Europe, not Italy.
My 23andMe test also shows less than one percent of South Asia, sub-saharan Africa, east Asia and native americans. That may be true, says Chakravarti, because the genetics of people on the mainland are so different, and South Asia can’t be like the europeans. “It will be very easy to address the differences between the African genome and the east Asian genome,” he said. “But it is much more difficult to resolve the same differences between parts of east Asia and parts of east Asia.”
I also learned that although I got half of my genes from my mother, they probably wouldn’t reflect her.
We do have the genes we inherit – each parent has 50 percent of the genes. But a process called recombinant means that each egg and each sperm carries a different combination of parental genes, says Elissa Levin, director of genetics and policy and clinical affairs at Helix.
She said: “when we talk about fifty percent of inherited from the mother, one may be your north-western Europe part of the restructuring gave you more, rather than the Italian part of your mother’s ancestral DNA. That’s why siblings can have different bloodlines.
These companies compare their DNA samples with those of generations of people living in certain regions of the world. These samples come from databases that all scientists can access, and they may also collect their own data.
“We can see, what is the specific markers, we are studying what is the specific part of DNA, this will help us determine,” these people from this part of the northern or southern Europe or south east Asia, “levin said.
As companies collect more and more samples, their understanding of the identity of a particular heritage person should be more accurate. But now, the smaller the percentage of the population in the database, the less certainty they have. Mr. Levin said the spiral chose not to report smaller percentages.
23andMe reports the results with a 50 percent confidence interval – they are sure the location is correct. To increase the level of confidence to 90%, which means that you are 90% sure of the location of a region, and the 1.6% of my Italian population is lost in Italy.
Lineage testing must also take into account the fact that humans have migrated for thousands of years, mixing DNA. In response, the company’s analysis involves what levin calls “random opportunities.” The computer must decide.
The ancestors must make a judgment. Robin Smith, senior product manager at 23andMe, says their computer compares your 31 teams. “Let’s say a piece of your DNA looks the most British and Irish, but it looks a bit like French German,” he said. “According to some statistical measures, we will decide whether to call it the United Kingdom – Ireland or France – Germany, or we go up one level and call it Western Europe.”
How does he account for my situation?
“It’s a bit surprising,” he said. “But given the fact that you have some southern europeans and some French and German people, the picture becomes even clearer.
So, now, my Italian grandmother didn’t show up in these tests. Regardless – Chakravarti, levin and Smith say the results add to your life story. Deoxyribonucleic acid just makes you a part of you.