by Leslie Wolfe
She accepted the flashlight from his hand, and handed him her own. “No rush,” she whispered. “We can trade them back tomorrow. Please.”
He held her gaze for a second, then nodded again. “Good night, Melissa.” Then he walked slowly to his house and disappeared, closing the front door behind him without a sound.
Relieved, she closed the car window and resumed her search. She put the incriminating hair fiber in the plastic bag, then continued searching the car for anything else that could help her prove her husband’s infidelity. She found nothing more, and, an hour later, after going through all his pockets and his briefcase just as thoroughly, she finally went upstairs, to bed.
She washed her face and brushed her teeth, feeling numb. Yes, Derek was cheating on her, and that was now a certainty, even though a single hair fiber proved nothing. Locked inside the bathroom, under the bright vanity lights, she examined the hair again. Could it be from the mysterious, young woman he was following a few days earlier? It appeared to be the right length, color, and type, but she couldn’t be sure.
One thing was certain, though. Even when he’d asked about her day, a rare occurrence she hadn’t seen in months, he seemed more interested in what another woman was doing, not her. Even if that fed was a woman he’d never even met, he cared more about her. Melissa simply didn’t exist anymore.
She snuck under the covers, careful not to wake him up, trying to take up as little space as possible. She settled in a comfortable position and almost dozed off, when he turned around and put his hand on her hip, mumbling something, reaching lower.
She froze, afraid to breathe, her eyes wide open in the darkness of the bedroom.
34
Dance of Chromosomes
Tess was still sleeping when the conference terminal chimed, and she pressed the green button before Cat made it around the bed, probably with the intention of silencing the ringer, considering the look on his face. She smiled at him and he sat on the couch, resigned.
“Wouldn’t have it any other way,” she whispered, then unmuted the phone call.
Cat shook his head, smiling. “Yeah, kiddo, I know.”
“Hello,” she said in a raspy whisper, speaking close to the phone. It was early morning; people were still sleeping in that hospital, and the glass door, although shut, only gave them limited soundproofing. If she could hear the man next door coughing in the middle of the night, probably he could hear her speak on the conference IP phone.
“Rise and shine, beautiful, it’s a brand-new day,” Donovan said loudly, and Tess was quick to adjust the sound volume. “DNA’s back, with the lab’s many, unquotable compliments. In your inbox, if you please.”
“Uh-huh, one second,” she said, then fired up her laptop and adjusted her bed while it was starting. She still struggled to find a comfortable position, and had to sit more on her right side to avoid putting pressure on her sutures, but with the help of a couple of pillows, she was all set.
She opened the email attachment and scanned quickly through the first few paragraphs.
“What is this, the revenge of the lab nerds?” she asked, staring at what appeared to be a mumbo-jumbo of English-sounding words mixed together by an angry tornado. “I can read it, but I don’t really… You know what? Get me Doc Rizza on the line. I bet he’ll make some sense out of this report.”
“I’ll ping him with the conference call number,” Donovan replied, laughing. “They said you were going to say that, you know.”
“Yeah? What else did they say?”
“They said you’re crazy, if you’re thinking that DNA will give you the portraits of the men you’re looking for. They actually said, ‘bat-shit crazy,’ to be exact.” Donovan was still grinning; she could hear the amusement in his voice.
“Well, if anyone knows about bat shit, it’s those guys,” she replied, not in the mood to let that kind of attitude ruin her day.
“They said the technology is decades away from being able to give you the physical appearance of a person, based solely on DNA.”
“Tough luck; I’m not willing to wait a few decades. Any other pearls of wisdom you need to convey? Maybe something useful for a change?”
“No, not really,” Donovan replied, but the amusement in his voice was gone.
“I’m listening,” she insisted.
“They said that, um, being how understanding you were of their workload and priorities, they don’t mind if you hang yourself professionally with this aberrant use of science, the worst they’ve seen since the medieval inquisition used the swim test to prove witchcraft.”
“Why do they consider this a foregone conclusion test?” she asked, feeling more intrigued than insulted.
“What do you mean?”
“Back in the medieval days, they used to throw suspected witches into the water, with their hands and feet bound. If the women were innocent, they’d sink and drown, while witches would float. Everyone sunk and drowned, for obvious reasons having to do with physics, not wizardry, but all tests returned the same result. Foregone conclusion. Is that what they think will happen here?”
“Don’t take it up with me, take it up with them instead. I’m just the unwilling messenger.”
As he spoke, she felt the grip of anxiety churn her stomach. What if they were right? She knew close to nothing about DNA, and she’d demanded test results instead of consulting with them first. What if she was wasting valuable time chasing the DNA evidence, when there was little to be gained from it? The FBI lab had an impressive line-up of scientists and forensic experts; maybe she should ask their opinions before forging ahead on her own.
“Oh, by the way,” Donovan interrupted her introspection, “the lab returned the results of your spiked-up IV bag. Propofol and potassium chloride, enough to put out ten like you.”
“Oh.” She couldn’t think of anything to say. Propofol would have put her into a deep sleep, while potassium chloride would have stopped her heart. Perfect recipe for taking someone out quietly, without them even knowing it. She felt her throat constrict and swallowed with difficulty, then gulped some tea to wash away the chill that had crept up her spine.
“Good morning,” she heard Doc Rizza’s voice on the call. “I heard you want to talk DNA.”
“Hey, Doc,” she replied, thankful to be pulled away from her morbid thoughts. She immediately noticed her voice sounded deflated. She closed her eyes for a second, and called on her instincts to give her some direction. No matter what the lab had said, she was going ahead with her plan, at least until they had a better way. It wouldn’t be the first time someone did something they didn’t know it was impossible to do. “Can you please translate the DNA results into actionable information? I want to organize the two profiles with every bit of physical details we can derive from these tests.”
“Let’s start with the killer unsub,” Doc replied. “But first, let me tell you that we can’t translate DNA into firm, physical characteristics, not for every facial feature.”
“What do you mean?” Tess asked.
“Call it scientific guesswork, because that’s as good as it’s going to get. You’ll understand more as we go along.”
“Okay,” she replied, more confused than she cared to admit.
“So, our killer unsub is a Caucasian male of European descent. That doesn’t mean he wasn’t born in the United States,” Doc added quickly. “It just means his genetic heritage stems from European Caucasians. In short, he’s white, and we got a little lucky.”
“Why?”
“There has been significantly more phenotype study done on whites than on any other race. Simply put, it’s better understood how and in what measure genetics influence the physical appearance of whites. Our portrait will be a little more precise. Then, we got lucky again, because your killer has a cleft chin.”
“That’s genetic?”
“Yes, absolutely. We can’t tell how prominent, but he’s got a dimple on his mental region.”
“They call the
chin, the mental region? Really?”
“Yup. Comes from the Latin word for chin, mentum. We did a poor job translating into English, because the Latins used mentalis or mens for mind, but we use mental for both terms.”
Tess repressed a sigh, eager to move along. “What else can you tell me?”
“Earlobes are next. They can be attached or non-attached, and your killer’s got them attached. That doesn’t say anything about how pointy or floppy they are, or if they’re sticking out. You see, that’s the real challenge with this type of profiling. You know a few things, but—”
“But you have to assume for the rest, I know that, and I can live with it. Attached lobes, I got it.”
“He’s probably got blue eyes, and, most likely, brown hair.”
“Why probably and most likely? Aren’t these traits genetic?”
“They are, but they’re not fully understood, or are too complex to predict accurately.”
“I was counting on this, you know. I was counting on at least this much to know with some degree of certainty,” she said, having a hard time swallowing her disappointment. Maybe she was crazy after all. “Why can’t we be sure? Help me understand.”
“Okay,” Doc replied and shuffled quickly through some papers. “I’ll explain it as well as I can, and you stop me if I’m getting too technical.”
“All right.”
“Eye color is determined by variations in the HERC2 and OCA2 genes, but also variations in at least ten other genes. These other variations, and the interactions between variations are not fully understood yet. The degree of confidence for the phenotype characteristic ‘blue eyes’ is 89.74 percent. That means they have established that 89.74 percent of people with the same variations in genes HERC2 and OCA2 have blue eyes. They can’t ascertain what the other variations and their combinations might generate.”
“I’ll take 89.74 percent gladly. I feared it was worse. What about hair?”
“The genetics of hair color are not fully understood yet,” Doc said. “Genetics is a relatively young science, one that evolves with new technologies and with every single human whose DNA is mapped, compared, and analyzed by itself or in reference to others.”
“Okay,” Tess replied, sounding a little impatient.
“Without getting too technical, hair color is mostly dictated by two gene pairs. One is brown/blond, where brown is dominant, and blond is recessive. The other pair is non-red/red, with non-red dominant. Our unsub has the dominant brown hair, but there’s no telling what shade of brown that is. I don’t think genetics has fully established how shades of hair color are determined, or why some people’s hair color darkens with age. These shades of color are given by two pigments found in human hair. One is eumelanin and will determine how dark the hair is. The other, pheomelanin, will give hair the reddish orange hues. Genetically, we don’t know how to predict the concentrations of these hair pigments; we don’t know which gene variations will decrease eumelanin, for example, making your killer’s hair a lighter shade of brown hair, or almost blond. ”
“Ugh, Doc, so he could have any hair color, from light brown to black?”
“Yes, I’m afraid so, not to mention hair color can be so easily altered.”
She let a long breath of air leave her lungs. “I see.”
“But here’s a trade-off,” Doc added, “he’s got the Cs combination of the hair-type gene, what they call incomplete dominance, and that means wavy hair. Not curly, not straight, but wavy.”
“That’s precise,” she commented. “I wish we knew his hair color with that amount of accuracy.”
“Nose shape is next,” Doc continued undisturbed. “Several face-shaping genes have given us some insight into how his nose is shaped. Another incomplete dominance gives us a medium-sized nose; actually, this man’s nose is average from all points of view: width, pointiness, bridge, nostril size. Completely average nose, with slightly wider nostrils than the norm. Also average is the chin protrusion, per the incomplete dominance found in the EDAR gene.”
“That’s it? That’s all we have?”
“Height is the only physical trait we have left, and it’s the most uncertain of them all.”
“Great,” she muttered under her breath.
“In Caucasians, the heritability of height is 80 percent, and this man’s variants place him at above-average height. The lab recommended unofficially, under a pile of disclaimers, that we should add 5 centimeters, not more, on top of the average height for men of his genetic background.”
“Which is what?”
“Um, 183 centimeters, plus 5 more, that’s 188 centimeters.”
She rolled her eyes, and reached for her phone, to calculate what that meant.
“That’s 6 foot 2,” Doc added, before she could finish her calculation.
“Fairly accurate,” she said, with a smile in her voice.
“Everything is under a big caution flag,” Doc replied, “but we’re not done yet. We have some other interesting data, in the polygenic risk scores.”
“That’s diseases, right?”
“It’s more than that, and it’s less. These are predictors that speak to the likelihood of the individual to have a certain ailment, whether physical or psychological. These are predictors though, nothing more. The individual might or might not get the disease, depending on socioenvironmental factors, lifestyle, and so on. However, your killer stands out with a very high likelihood to have schizophrenia, even if undiagnosed.”
“That’s not going to help much,” Tess replied, thinking hard. If he wasn’t diagnosed, how could she trace him?
“It could help though. Those with genetic predisposition to psychoses have an array of other ailments. Anxiety, major depression, addictions. This is a marker that could be useful; chances are this man is on some kind of anti-psychotic or anti-depressive medication, or has been at some point in his life.”
“Huh… very useful, Doc, so has the rest of America.”
Doc Rizza laughed. “Every itty-bitty morsel counts, that’s what you once told me, ad literam.”
“Very true. What other morsels can you share?”
“Um, nothing much. His other genetic health predispositions are incredibly average, except this one: he’s almost twelve times more likely to get severe migraines than the average individual.”
“Migraines?”
“Severe ones, yes.”
“Okay, thanks for that profile. Now, how about the rapist, Doc?”
“Male, Caucasian, blond hair, and, if you recall, with blond hair there’s less room for error. Straight and fine, with strong markers for balding on chromosome 20. Attached earlobes, but no cleft chin in this unsub. A slightly aquiline nose and a stubborn, protruding chin. Brown eyes, or better said, non-blue. They could be any color from hazel to black.”
Tess took notes on her laptop as fast as she could, grumbling quietly on occasions when she didn’t like what she was hearing.
“Average height, so 183 centimeters is the best guess in height. That’s 6 feet even.”
“Got it. Diseases?”
“We might have some luck with your rapist. He’s got a genetic condition, autosomal dominant polycystic kidney disease or PKD.”
“Meaning what? I’ve never heard of it.”
“It’s one of the most common genetic mutations, causing cysts to develop on one or both kidneys.”
“That means there’s a specific drug we could trace?”
“Unfortunately, not. Antibiotics might be prescribed, but he could also be asymptomatic. Sometimes, PKD doesn’t manifest until mid-life. On the other hand, he could be on dialysis; there’s no way of knowing.”
“Any other— what did you call those— health predictors?”
“Health predispositions, yes. He’s at risk of developing dementia in his old age, and has an 18 percent higher-than-average risk of stomach cancer. Nothing else we could use, I’m sorry.”
Tess massaged her temples, trying to think. She didn�
�t have much, but she had more than she did the day before, and that, in her book, was called progress.
“One other thing, I almost missed it,” Doc added. “Their ages.”
“You can tell age from DNA?”
“Yes, you can. There are four, age-associated DNA markers that can give an accurate estimate of age, based on methylation.”
“On what?”
“Chemical reactions that take place in human DNA with age. This test is actually being used in Europe in routine forensics, in the Netherlands if I’m not mistaken. Anyway, the margin of error is less than four years; the younger the subject, the higher the accuracy.”
“Give,” she said, feeling more hopeful.
“The killer is about thirty-five, give or take three years, and the rapist is thirty-one, also give or take three years.”
“It matches the behavioral profile,” she concluded. “Thanks, Doc, you’re amazing, like always.”
“What are you going to do with all this?” Doc Rizza asked.
“I’ll get portraits done,” she replied. “Just like we normally do when we have a witness. This time I’ll be the witness, that’s all. I’ll ask Donovan to send me the best sketch artist who ever lived.”
“Copy that,” Donovan confirmed.
“And do what?” Doc Rizza reacted. “Take the killer unsub, for instance. His face could be wide or narrow. His forehead could be tall or not. His eyes could be wide or small. He could have long hair and a beard, or be completely clean shaven.”
“I know all that, but it’s not going to stop me. I’ll use approximations and averages for everything we don’t know; that’s why I need the best artist there is.”
“Even so, you could get the face of no one specific, who’s going to generate more errors and false leads than anything,” Doc Rizza insisted, although sounding less convinced.
“It’s a risk that I’m willing to take,” she replied. “Otherwise, what the hell would I be doing in here all day, twiddling my thumbs?”
