Identical (11 page)

“A human gene consists of hundreds or thousands of combinations of the chemical building blocks, adenine-A for short-cytosine, C, guanine, G, and thymine, T. One segment of the hemoglobin gene, to pick an example in the blood, is CTGAGG. A copy-number variation is like a typo. So CCTG
A
GG could be switched to CCTG
T
GG, with thymine substituted for adenine in the genetic sequence. CNVs probably explain why only one twin gets what we think of as a genetically influenced illness. The example I just gave you, with the A switched to a T in the hemoglobin gene, leads to sickle-cell disease.

“Most CNVs are probably benign, and some may prove positively beneficial. They occur in all individuals, not just in identical twins, probably as part of nature’s great ongoing experiment. My own research suggests that about two-thirds of CNVs occur after conception, as part of fetal cell division.”

“So that’s what might be different between Cass and Paul?” she asked. “These CVNs?”

“CNVs,” said Yavem, smiling patiently. The DNA lab visible beside Yavem’s desk through a wide window was far less dramatic-looking than Evon might have expected, not all that different in appearance from where she’d taken high school chemistry, the same collection of beakers and bottles, microscopes and computers and black counters. There were rows of test tubes in blue plastic racks, capped with white stoppers. It was a small space, undoubtedly so the risks of contamination could be controlled, and the three gowned workers within were pretty much elbow to elbow. One man in a surgical mask kept removing his gloves so he could type on his laptop, before turning back to his microscope. A woman was looking at a slide with a piece of red equipment that looked for all the world like a fire alarm.

“Now the theory meets practice. My colleagues in Alabama were able to isolate identifiable CNVs only in roughly 10 percent of twins. So given where we are today, nine times out of ten, you are not going to be able to differentiate identical twins genetically. And even if you found a CNV, it does not occur in all cells of that type. With blood cells, only 70 to 80 percent would contain that CNV, so you would need to confirm your results with a number of specimens.”

“I got it,” she said. There was only a 10 percent chance of success, without considering other problems. “But it is possible? You might get valid results?”

“In theory, of course. But you must understand, even if we found one or more CNVs between your twins, and even if that same CNV occurred in blood at the crime scene, that would not necessarily mean that twin was the perpetrator.”

“What?”

Yavem maintained his mirthful air and smiled again.

“Imagine the CNV we detected was the one I mentioned in the hemoglobin gene. Unfortunately,
many
people have sickle-cell disease. We would know that only one twin could have contributed the blood at the scene, but
not
that the blood came from that twin. To make that conclusion, you will still need to do more standard DNA testing, which invites a host of new problems. How much, Ms. Miller, do you understand about DNA comparisons?”

“I started out in the FBI and used to know some,” Evon said. “But it’s a little like high school math. Every time my nieces or nephews show me their homework, it seems to have nothing to do with what I saw from the older ones a couple of years before.”

Yavem loved the analogy. He laughed for some time. It was easy for Evon to see why he was in such high demand as a witness. He was charming, with no trace of arrogance. And no matter who hired him, he would get on the stand without an agenda. Everything about the man said he was above pandering.

“All right,” he said. “I’ll go back to the beginning. Roughly 99 percent of the genome is the same in each human. But the genes of every person contain certain regions of DNA sequences that differ from individual to individual, basically in terms of how often they repeat. By developing a technique to examine these DNA repeat sequences-by finding an enzyme that could break them apart, actually-Sir Alec Jeffreys in England created human identity tests in 1984. Those tests look to a small number of loci in the genome where repeat differences have been studied and cataloged so we know how often they occur. With matches at some or all of those loci, we can then say statistically that only one person in a million, or even a billion, has the same DNA repetitions.”

Trying to take this in, Evon looked up to the acoustical tiles on the ceiling. This was basically what she’d first learned at an in-service at Quantico, when she went back for further training in the early nineties.

“But that’s not hard these days, is it?”

Yavem smiled. “That depends. Do you know how these specimens you want to test have been stored?”

“Not yet.” The truth, which she wasn’t ready to confess, was she didn’t even know if the evidence still existed. Tim had dug up the inventories recorded by the state and local evidence techs, so she knew what had been collected originally. As far as Evon could tell, after making a few phone calls, the state crime lab tended to preserve evidence in murder cases as a matter of protocol. But that was a rule with many exceptions. Exhibits frequently were never retrieved from the court file, or after a case ended. Rather than retransmitting the evidence to the records section, troopers and deputy PAs frequently dumped it in a drawer, where the specimens moldered until they were thrown out. But the prominence of the Kronon case, with a gubernatorial candidate’s daughter as the murder victim, made it more likely things had been done by the book. If so, the blood by the window, which had to be from the murderer, would be of special interest.

“You can be all but certain,” Yavem said, “that evidence gathered in 1982 was not stored in a way designed to preserve DNA. No fault of the techs for not being mindful of a technology that didn’t exist. But DNA breaks down over time, just like any other cellular material. Blood specimens might have been refrigerated. But we can also extract DNA from fingerprints-since they’re really sweat residue-but no one really practices precise temperature control in storing prints. Then there’s the issue of contamination. No one knew that they should be careful about shedding their own DNA-skin cells, for example-into the specimens they were collecting.

“Given the risks of degradation and contamination, your best option is the most widespread form of testing today, STR testing-short tandem repeat testing-and in particular Y-STR testing, which focuses on the Y chromosome. Y-STR is discriminating with very small specimens and the Y chromosome, due to its structure, does not degrade as quickly. And, of course, you don’t have to worry about contaminating cells contributed by females, because only males have a Y chromosome.”

“And what’s the chance that Y-STR works?”

“Fairly high,” Yavem said. “But the problem of degradation and contamination would exist not only in doing the Y-STR examination. It would also be a significant factor in applying the two tests used to prospect for CNVs, processes using technologies called 32K BAC and Illumina BeadChip.”

Yavem then outlined a full testing protocol for Evon, mostly so she understood everything Hal would have to pay for. First, they would examine the DNA to determine that Paul and Cass really were identical twins, hatched, as it were, from the same egg. There were thousands of pairs of twins around the world who had learned in recent years, after the discovery of DNA, that they were fraternal, not identical. Second, Yavem would do Y-STR testing to establish that the blood at the scene had come, to an overwhelming degree of probability, from Cass or Paul. Third, they would do these two other tests hoping to find a copy-number variation between the twins. And then, fourth and last, they’d try to find the CNV in the same genetic location in a number of blood specimens collected at the scene.

“That’s why I would say,” said Yavem, “at the end of the day, the chances of getting a scientifically reliable result are no better than one in one hundred. A long shot in anyone’s book. Yet we would be most happy to try. It would be a very interesting project, and one with some obvious research implications.”

She reviewed the last details with Yavem about cost and timing-the CNV tests were proprietary and would have to be performed at the facilities that owned that software, meaning the process all told would take at least three weeks. She thanked him lavishly and asked him to invoice her for his time, then headed back to the office to try to explain all this to Hal.

Hal was pretty much as Evon had left him that morning, canted back in his desk chair in his huge office, amused by what he was seeing on a large plasma screen on his wall. He might as well have had a bowl of popcorn beside him.

When she’d gone in to tell Hal she was on her way to see Yavem, Kronon had been reading his employees’ e-mail. Every company these days informed workers that they could not expect e-mails on the company account to remain free from internal inspection. But Hal took that as license for occasional surveillance. Originally, the feed had been set up so Evon’s staff could catch a little jerk in the leasing department who was peddling the names of potential tenants to a competitor. But Hal never turned off the stream. He liked to see who was passing links to porn sites or saying critical things about him, or to pick up office gossip. As far as Evon knew, he did nothing with the information, which he digested like a disinterested god entertained by the foibles of the mortals below.

Now, Hal was turned toward the screen and chewing on his thumbnail as he viewed the finished version of the commercial featuring Georgia. Evon hadn’t seen the completed ad and watched it straight through with him. It was very strong.

“It goes on the air tonight. Let’s see his poll numbers after this,” Hal said.

Hal’s vast office was paneled in a richly grained pale wood, sycamore, Evon believed, with built-in cabinetry to match. On the far bookshelf, he maintained his little shrine to his sister-replete with her college yearbook photo, a piece of childhood pottery, and pictures of Dita beside his parents or his favorite aunt, Teri. A nearer shelf was set aside for photos of his mother and father. In fact, an oil portrait of Zeus, one of several in the ZP offices, hung outside the door. The credenza under the TV, by contrast, was dedicated to a three-deep forest of pictures of Hal’s own family. Say whatever you might about Hal, but he was a dedicated father and husband. He boasted too much about his kids, but that was due to a radiant love. Mina and he had four children, the eldest two boys done with college. Hal hoped they might be lured into the business, but they were both committed to humanitarian projects. His older son, Dean, was doing AIDS work in Africa. All of Hal’s kids, even the two girls, who were still in high school, regarded their father’s political views as antediluvian, and Hal tolerated their opinions as an amusing failing of youth, even though he would have chewed through the throat of anyone else who said such things. As for Mina, he doted on her. He called his wife three or four times a day, and was invariably gentle with her, and happy to follow her directions, which he accepted as a sign of love. She laid out his clothes every morning. He was, truly, one of the most happily married people Evon knew.

“One in a hundred, huh?” he asked, following Evon’s summary.

“And at least a quarter of a million dollars.”

Hal pondered. “But he said he’d do it, right?”

“We can make the motion to Judge Lands. Yavem will give us an affidavit saying that he believes it’s possible to get valid results. But it’s new science, Hal. The
Frye
hearing to establish the reliability of the test could go on for a month, just by itself.”

Hal was thinking, but his heavy face was bobbing agreeably as he considered the prospects. Evon wanted him to sort through the potential results before he made up his mind, which would then be permanently set like concrete.

“Look, Hal, I’ve been thinking about this, and we need to consider what happens if it goes the other way. We may thread the needle, as Yavem puts it, and find that the blood is Cass’s. In fact, if we get a positive result, that’s still the most likely one, when you remember the guy pled guilty. That’s a big risk. Your reputation will never be the same. And Paul would become a giant martyr who could just start moving his furniture into city hall.”

Hal listened to her attentively, as he generally did, his goggle eyes clearly focused behind his dense lenses.

“Do it,” he said then. “I realize this could boomerang. But they killed my sister, and as sure as I’m sitting here, I know Cass and Paul have been hiding stuff all these years. I
know
it. And I want the truth. I owe it to Dita.”

Back at her desk, Evon called Yavem’s lab, then settled in with everything that had piled up, most of it concerning the YourHouse deal. ZP’s investigators had discovered that decades ago there had been a small paint factory on part of the site in Indianapolis, which explained what Tim had overheard when he was tailing Dykstra. But the soil borings so far had turned up none of the expected contamination. Dykstra had feigned outrage and was demanding that Hal sign the letter of intent this week or call off the deal. Hal could not demand a price concession yet-ZP was supposed to pay 550 million dollars, four hundred of it in cash to be raised by cross-collateralizing the equity in the shopping centers-and as a result, Hal was whistling Evon down to his office five times a day, demanding a report on literally every new hole that was dug.

She did not get out of the office until well past 8. As her BMW 5 Series ascended from the garage under the ZP Building, Evon called Heather and received a text in reply. “Workg late. Crap More.” ‘Crap More’ was Heather’s code for Craigmore, the demanding client.

The condo they shared was in a new building, thirty stories of glass. They had chosen the apartment together, although Evon had paid for everything-Heather basically wore every dollar she made. Heather had furnished, twice now, with the same spare elegance with which she dressed. There was a full wall of windows over the river, and a lot of tidy minimalist furniture that required the place to be neat as a pin to achieve the desired effect. It was beautiful in the perfect way Heather was beautiful, but Evon never felt fully at home. Left to herself, she’d prefer overstuffed chairs and a couple of dirty socks on the floor amid a scatter of magazines. Her discomfort was greater when she was here by herself.