Technically, two. The little green digits said 5:59.
“Oops. Sorry.”
“Mm.”
“That means I woke you.”
“I had to get up anyway to answer the phone.”
“That line is ancient.”
“It’s way too early for anything original.”
“Thought you’d want to know. Floating Florence gave up some DNA.”
“Floating Florence?”
“Nightingale? As in nurse? The Hemmingford corpse? Your lab pals did STR. Whatever that is.”
“Short. Tandem. Repeat.”
“Sorry. Too. Rarefied.”
“Come on, Ryan. STR has been around since the nineties.”
“So has cloning. Still no one gets it.”
“It’s standard for most forensic DNA labs.”
Ryan was smart, genius at some things. Science was not one of them. Silence meant I was sailing right over his head.
Great. Biology 101 at dawn.
“Each DNA molecule is made up of two long chains of nucleotide units that unite down the middle like rungs on a ladder. Each nucleotide unit is composed of a sugar, a phosphate, and one of four bases, adenine, cytosine, guanine, or thymine. A, C, G, or T. It’s the sequencing of the bases that’s important. For example, one person can be CCTA at a certain position, while another is CGTA. With STR, four or five sequence repeats are analyzed.”
“Why?”
“Shorter repeat sequences can suffer from problems during amplification. Also, some genetic disorders are associated with trinucleotide repeats. Huntington’s disease, for example. Longer repeat sequences are more vulnerable to degradation. And they don’t amplify by PCR as well as shorter sequences.”
“Ten words or less, how does STR work?”
“Ten?”
“I’ll go twenty, that’s my top.”
“First, you extract nuclear DNA from your sample. Next, you amplify specific polymorphic regions—”
“Flag on the field. Jargon violation.”
“Regions on the genome where there is variability. You amplify, you know, make more copies. Then you determine how many repeats exist for the STR sequence in question.”
I was oversimplifying for Ryan’s benefit. It seemed to be working.
“Once you’ve got the genetic fingerprint from your suspect or unknown, in this case the Hemmingford floater, you compare it to that of a family member, right?” he asked.
“Even better, you compare a sample from your suspect or unknown to another sample taken from him or her before death. Extracted or saved baby teeth. Saliva from a toothbrush. Mucus on a tissue.”
“So our next step is to swab Plato’s cheek or find Spider’s own snot.”
“Nice.”
“You said it.”
“With much more élan.”
“But similar connotation. Think Daddy will agree to open wide and say ahh ?”
“I don’t know,” I said. “It’s doubtful he’s going to like the results.”
“Very,” Ryan agreed.
For several seconds empty air hummed across the line. Then Ryan asked about Katy.
“She’s still pretty bummed,” I said.
“You never mentioned a boyfriend. Did you know she was head over heels for the guy?”
“No.”
Absence? Inattentiveness? Whatever the reason, my ignorance spoke of remoteness.
“She’ll come around.”
“Yes. How’s Lily?”
“Attending group and keeping appointments with her psychologist. Her color’s better and I think she’s gained a little weight.”
“Don’t tell her that.” An attempt at levity. It fell flat.
“The kid’s saying all the right things. But I don’t know.” Ryan drew a deep breath, exhaled. “Sometimes I get the feeling she’s just going through the motions. Telling me what she thinks I want to hear.”
Not good. Ryan’s instincts were usually dead-on.
“And she and her mother are like fire and ice. Lutetia’s trying, but patience is not one of her strengths. Lutetia says something, Lily overreacts, Lutetia comes down hard, they both explode, and I end up dealing with the aftermath.”
“Sounds like they need a break from each other.”
“You’ve got that right. But I can’t have Lily living with me. At this
“Oops. Sorry.”
“Mm.”
“That means I woke you.”
“I had to get up anyway to answer the phone.”
“That line is ancient.”
“It’s way too early for anything original.”
“Thought you’d want to know. Floating Florence gave up some DNA.”
“Floating Florence?”
“Nightingale? As in nurse? The Hemmingford corpse? Your lab pals did STR. Whatever that is.”
“Short. Tandem. Repeat.”
“Sorry. Too. Rarefied.”
“Come on, Ryan. STR has been around since the nineties.”
“So has cloning. Still no one gets it.”
“It’s standard for most forensic DNA labs.”
Ryan was smart, genius at some things. Science was not one of them. Silence meant I was sailing right over his head.
Great. Biology 101 at dawn.
“Each DNA molecule is made up of two long chains of nucleotide units that unite down the middle like rungs on a ladder. Each nucleotide unit is composed of a sugar, a phosphate, and one of four bases, adenine, cytosine, guanine, or thymine. A, C, G, or T. It’s the sequencing of the bases that’s important. For example, one person can be CCTA at a certain position, while another is CGTA. With STR, four or five sequence repeats are analyzed.”
“Why?”
“Shorter repeat sequences can suffer from problems during amplification. Also, some genetic disorders are associated with trinucleotide repeats. Huntington’s disease, for example. Longer repeat sequences are more vulnerable to degradation. And they don’t amplify by PCR as well as shorter sequences.”
“Ten words or less, how does STR work?”
“Ten?”
“I’ll go twenty, that’s my top.”
“First, you extract nuclear DNA from your sample. Next, you amplify specific polymorphic regions—”
“Flag on the field. Jargon violation.”
“Regions on the genome where there is variability. You amplify, you know, make more copies. Then you determine how many repeats exist for the STR sequence in question.”
I was oversimplifying for Ryan’s benefit. It seemed to be working.
“Once you’ve got the genetic fingerprint from your suspect or unknown, in this case the Hemmingford floater, you compare it to that of a family member, right?” he asked.
“Even better, you compare a sample from your suspect or unknown to another sample taken from him or her before death. Extracted or saved baby teeth. Saliva from a toothbrush. Mucus on a tissue.”
“So our next step is to swab Plato’s cheek or find Spider’s own snot.”
“Nice.”
“You said it.”
“With much more élan.”
“But similar connotation. Think Daddy will agree to open wide and say ahh ?”
“I don’t know,” I said. “It’s doubtful he’s going to like the results.”
“Very,” Ryan agreed.
For several seconds empty air hummed across the line. Then Ryan asked about Katy.
“She’s still pretty bummed,” I said.
“You never mentioned a boyfriend. Did you know she was head over heels for the guy?”
“No.”
Absence? Inattentiveness? Whatever the reason, my ignorance spoke of remoteness.
“She’ll come around.”
“Yes. How’s Lily?”
“Attending group and keeping appointments with her psychologist. Her color’s better and I think she’s gained a little weight.”
“Don’t tell her that.” An attempt at levity. It fell flat.
“The kid’s saying all the right things. But I don’t know.” Ryan drew a deep breath, exhaled. “Sometimes I get the feeling she’s just going through the motions. Telling me what she thinks I want to hear.”
Not good. Ryan’s instincts were usually dead-on.
“And she and her mother are like fire and ice. Lutetia’s trying, but patience is not one of her strengths. Lutetia says something, Lily overreacts, Lutetia comes down hard, they both explode, and I end up dealing with the aftermath.”
“Sounds like they need a break from each other.”
“You’ve got that right. But I can’t have Lily living with me. At this
Similar Books
