“When do you think we can start?” Aria said. Some of Madison’s excitement was beginning to rub off on her.
“Tomorrow,” Madison said. “Why not? I’ll find out what the commercial DNA companies would like for samples since we won’t be able to send saliva, which is what they usually use.”
“I’m sure I can get body fluid or tissue samples from both the mother and the fetus. You’ll have to let me know what they want.”
“That reminds me,” Madison said. “What was the sex of the fetus?”
“It wasn’t yet definitive,” Aria said. “We estimated the age to be around ten weeks. At that stage it’s not easy to tell, since the forming penis and clitoris are around the same size until about fourteen weeks. If I had to guess, I’d say male.”
“It would be a big help if it were a male,” Madison said.
“Why is that?”
“Because the Y DNA is inherited only from the paternal side.”
“Even I know that, because it is the Y chromosome that determines the male gender. Why is that any better than the autosomal DNA for genealogy?”
“It’s not better, it’s just different and additive,” Madison said. “But mainly because it can provide a surname. If we can determine the proper family name, the field of significant matches narrowsdecidedly, provided there wasn’t anything to mess things up like an adoption.”
“Why would an adoption mess things up?” Aria asked.
“The surname changes but the Y chromosome doesn’t. It can really cause a problem when trying to construct family trees, and it is family trees that we’ll need to use if we don’t get a really close match right away, which we probably won’t. There’s too much chance involved.”
“Okay,” Aria said. It was progressively apparent to her that she needed to read up on genetic genealogy. She’d not known it was as complicated as it seemed to be, although as a doctor she should have. Having studied biology she knew about chromosomal recombination, which was one of the main sources for heritable diversity. “What about mitochondrial DNA?”
“If we had the father’s DNA and were trying to reconstruct the mother’s, then mitochondrial DNA would be helpful. As you know, it is only inherited along the maternal line because the sperm doesn’t contribute mitochondria. All the mitochondria come from the ovum.”
“Of course,” Aria said. She felt a twinge of embarrassment for asking her question and appreciated Madison for not calling her on it. “Obviously I need to get myself up to speed on all this genetic genealogy. Are there any particular books that you’d recommend?”
“Oh, yes,” Madison said. “There are two, actually. The one that’s more general is calledThe Family Tree Guide to DNA Testing and Genetic Genealogyby Blaine Bettinger. The other one, which will be more helpful for our search, isThe Adoptee’s Guide to DNA Testingby Tamar Weinberg. Adoptees have been using genetic DNA to search for their natural parents from the very beginning of DNA genealogy with improving success. The other group of people who have surely benefited from genetic genealogy’s developing power are those who have been conceived with donor sperm. What this group in particular has learned over recent years will help us a lot since that isessentially what we’re doing, and there are a number of websites who might be willing to help us.”
“How are you ladies doing?” Alex asked. He’d approached and waited for an opportunity to speak. The women had been locked in conversation. “Can I get you any more food or drinks?”
“I’ve had enough,” Aria said.
“Me, too,” Madison said, although she quickly polished off the dregs of prosecco.
“How do you guys want to handle this?” Alex questioned, pointing to the glasses and the dishes in front of the women.
“I’ll take the check,” Madison said. Then, to Aria, she said, “I talked you into stopping here, so my treat.”
Aria stayed silent. If Madison wanted to pay, who was she to complain?
“What’s the quickest and easiest way to get those books you mentioned,” Aria asked while Madison was finger-signing the reader that had her credit card poked into its base.
“The quickest way is to come back with me to my apartment,” Madison said. “You can borrow mine, provided you don’t mind if they’re underlined and a bit dog-eared. I’ve read both several times.” She finished signing and handed the device back to Alex, who immediately produced a receipt.
“Thank you, ladies,” Alex said. “Come back and see us again.”
“Where do you live exactly?” Aria said to Madison.
“West Seventy-Third between Columbus and Amsterdam.”
“That’s close to me,” Aria said. “I live on Seventieth between Columbus and Central Park West.”
“That’s certainly convenient enough. Do you want to come and get the books? If you want to get a jump on genetic genealogy, I’d recommend it for sure.”
“Okay,” Aria said. “We can take a rideshare to your apartment, and I can walk home from there.”
