GCT CCA TTC TTC GAG TTA TGG GCA GTG TTT GCA GTC TTT ACG TTT TTA AAT CGT GGC GTT GTG ATG TTC...
Whenever the screen froze, a number flashed up on the screen, signifying which of the twenty-three pairs of chromosomes the DNA code related to. Next to it was a percentage figure, denoting how much of the total genome had been analyzed. Then the speed scrolling would start again until the whole genome had been analyzed. The final percentage was 32 percent.
The screen changed one last time to reveal a chart showing all twenty-three chromosome pairs down the left column and the percentage of readable DNA in each of them down the right.
"
All chromosomes corrupted
," informed DAN. "
No exceptional
genes found in readable sections. More information needed to
extrapolate missing segments
."
"No good?" asked Alex.
"No," said Tom. "But since we've only been able to read a third of the sample it doesn't tell us much. DNA is pretty robust stuff but because of the corrosion of the nail and the way the blood cells have decayed over time, major sections of the genetic code are either illegible or destroyed. So all we know for sure is that there are no unusual genes in the third we can read."
"So what now?"
"We wait for the tooth DNA. It's been protected by the enamel surface so it should be fine. We know from studies of the DNA of Egyptian pharaohs, sometimes a thousand years older than this sample, that genetic material taken from within a tooth or bone is the most robust form of DNA there is."
As usual, Alex wanted to know more. "But how do you
know
there's nothing there?"
His father liked words, not dumb numbers, and he wasn't used to being the only boy in class who didn't understand the blackboard. So Tom pulled a printout off the printer next to DAN. "Look, I'll show you," he said, spreading out the paper in his hand. "It's easier to see the raw data on a printout."
Jack walked over to join them.
Tom held the printout so both could see it. "This should be clearer."
"Are these the chromosomes?" asked Alex, putting on his glasses, and pointing at the numbered headings.
"Yeah. Imagine it's a map of the United States where there are only twenty-three states. The twenty-three pairs of chromosomes are the states, and the genes are like towns or cities within these states. Within the genes, you've got the base letters that are like individual citizens. The order of these letters determines what proteins each gene produces. These proteins maintain and develop your body. Make your hair grow. Digest your food. Repair cuts and so on. This topline data sheet is only concerned with genes, and unusual ones at that. You know? Genes that are outside or on the extreme edge of the standard healthy genome."
He pointed to the "abnormal genes" box on the printout under the number twenty. "If there's anything unusual here you would see the genes highlighted. But as you can see, all the genes in this chromosome are within the bounds of normality. The ones that haven't been corrupted by the corrosion on the nail anyway." He indicated the top of the sheet. "If you look here, you can see that for the total genome--the intact bit we were able to scan--there are no really unusual genes. Nothing."
"So you hope that any unique genes are in the seventy percent you couldn't scan?" asked Jack.
"Yes."
Jack turned back to the Genescope where Jasmine and Bob were checking the tooth scan. "And you believe the more complete DNA from the tooth will allow us to see that?"
"Maybe."
Alex pored over the printout. "How does DAN know where the genes are within all the letters?"
"Only a small percent of the three billion letters of human DNA actually code for functioning genes. The others, particularly the so-called introns, don't appear to do anything at all. Every gene is bracketed by a particular combination of letters called stop and start codons. These tell
DAN where to look. For example, most genes start with the amino acid methionine--that's ATG. So whenever DAN reads ATG it knows a gene is beginning. TAG on the other hand tells DAN when the gene is finished. So it only bothers to read the letters between these markers--in the so-called Open Reading Frames. It ignores the rest as gibberish."
"
Scan of Nazareth Tooth complete. Results available. Detail
Gene Search option selected
," interrupted DAN, behind him.
"We've got a good read," said Jasmine, the excitement audible in her voice. "Virtually perfect."
Tom turned with the others back to the screen.
"
No genes found outside or on extremes of Standard Human
Genome
," announced DAN abruptly.
"What?" said Tom, stunned. He couldn't believe it.
Jasmine released a huge sigh, but whether it was of dismay or relief, Tom couldn't tell.
Jack muttered a quiet but distinct "Shit."
Bob and Nora stood staring at the screen.
Alex just shook his head and frowned.
Tom checked the topline analysis. The genome scan showed no unusual genes at all. Nothing. It wasn't possible. The most remarkable thing about the tooth genome was that it was too perfect. It was an almost exact fit with the notional Standard Healthy Genome that everyone was compared against, but was always different from. Christ's genome--if indeed it was his--had only one real abnormality. It was too normal. No defect
at all
was visible in his genetic makeup. But apart from that, nothing.
Then Alex's scholastic tones cut through the awkward silence. "It's probably a stupid question, But could the genes you're looking for have different stop and start codons--ones that DAN doesn't recognize?"
Tom looked at Jasmine and could see she was thinking the same thing. It
was
a stupid question; one that no self-respecting geneticist who knew the first thing about the all-powerful Genescope would ask. Which was exactly why Tom
didn't
dismiss it.
"But how can we find the new stop and start codons?" asked Jasmine as if reading his mind.
"We could try homology," said Bob Cooke. "But we'd need a different stretch of DNA containing the same genes."
"Homology?" asked Alex.
"Yeah," said Tom. "DAN can search two stretches of DNA and try to find a long sequence of letters that is identical in each. The odds of this sequence being a gene are very high. We then take its first and last letter combinations and Bingo! We've found our new stop and start codons."
"But we do need a second stretch of different DNA that contains one or more of these genes," reminded Jasmine.
"What about that genome you found on IGOR when you were looking at the genes of faith healers?" asked Tom, desperate to try anything. "What's his name? The Brit who was cremated last year; the one who could ease rheumatoid arthritis with his hands."
Jasmine turned to the PC on the workstation next to DAN and punched the keyboard with nimble fingers. "Anderson, right?"
"Yeah, that's the one. Run an accelerated homology study on him and the Christ genome."
Jasmine's fingers moved again. "It's done. I've given DAN all the data and it should give us an answer in the next few minutes."
It took only four and a half minutes for DAN to announce that both genomes shared an identical sequence of fifty-seven thousand base letters, and that the projected stop and start codons were each nine letters long--GCCTGACCG to open the reading frame and TCGAGGTAC to close it. It took Jasmine less than thirty seconds to recalibrate DAN to search the total Christ genome for genes between these new brackets.
There followed a pause of some minutes in which Tom heard no sound, not even a breath from the others.
Then DAN spoke. "
One extra gene found outside the human
genome on the paternal copy of chromosome 7
."
Numbers danced across the screen, and this time Tom's eyes danced with them. He was finally seeing evidence of what he'd only hoped for till now.
DAN made a sound as if clearing his throat and spoke again.
"
One extra gene found outside the human genome on the pa
ternal copy of chromosome 10
."
Two genes. There were two genes. He couldn't wait to ask DAN what they coded for, but before he could speak the Genescope began to growl, as if trying to think through a particularly difficult problem. And when it spoke again Tom fancied he heard surprise in its metallic monotone.
"
Third gene found in paternal copy of chromosome 18. No more
genes outside the human genome
."
Tom felt a sudden rush of relief and elation, his disappointment forgotten. The owner of the tooth possessed three genes that most--if not all--other humans did not. He looked around him and caught the look on Jasmine's face. The others had similar expressions of silent shock on their faces.
It was Jack who spoke first. "What do these genes do?" he asked. "Are they worth getting excited about?"
"Let's find out." Tom turned to the Genescope and said, "DAN, please estimate the function of these new genes."
The Genescope's growl lowered in tone, and the lights on the ovoid body blinked. Then the growl returned to its normal pitch. "
Initial extrapolation of coded amino acids indicate that the gene
on chromosome 7 should code for proteins with DNA and cell re
pair capability. The gene on chromosome 10 has a cell control
function. The third gene on chromosome 18 is too complex to give
any initial indication of function. These are only estimates based
on supplied data. Laboratory confirmation is necessary
."
Bob Cooke looked at Tom, his eyes wide with the possibilities. "Incredible. The first gene can make or repair DNA. And the second can control cell growth. Perhaps they're smart genes--one acting as a cell accelerator and the other a brake on proliferation. Together they could check the fluctuations in the rest of the genome."
"If DAN's extrapolation is correct," cautioned Jasmine.
"Of course," said Tom, waving away her concerns. "We'd need to check the findings in the lab, and we've
still got to find out what the third gene does. But if they are smart genes controlling the rest of his DNA, that would explain why Jesus' genome was so healthy. Perhaps they gave him a superior immune system?"
"One he could pass on to others?" chipped in Bob with an excited grin.
Tom smiled. "Well now, that's the sixty-four-thousand-dollar question. That's what we need to find out in the lab." He suddenly thought of Ezekiel. "Jazz, will we able to find a match on IGOR with these genes?"
Jasmine shrugged. "Should be able to. It'll take time to recalibrate the database to the new stop and start codons but we already know that Keith Anderson had one of the genes. So sure, if a match exists on IGOR, then we might find a live one eventually with all three."
Tom walked over to the virtual reality headset protruding from the beak of the Genescope. "Let's take a closer look at the genes. DAN, give me eye presentation." He felt the others crowd around him as he donned the headset. But they were soon forgotten as he concentrated on his journey into inner space. First he saw darkness, then the whole cell appeared below and around him. All the chromosomes, like continents of varying shapes, shimmered in their splendid hues. He knew the colors came from the magnetized dyes, but they made the spectacle seem more, not less real.
"Give me chromosome 7," he ordered DAN. "And take me to chromosome level resolution."
Immediately the scene in front of him shifted down to an even greater spectrum of colors. He was now focused solely on one chromosome and the DNA string of life contained within it. It was beautiful. His eye traveled along the rainbow spiral staircase of the double helix. He watched the magnetized dyes highlight the different nucleotide pairs, making the DNA strands stand out in 3-D. The new gene was stretched out before him, and just the sight made his chest tighten with excitement. This was one strip of the programming responsible for the development of the most famous and influential man who'd ever lived: Jesus Christ. And he, an atheist, was the first man alive to see the genetic
"abnormality" that helped determine his destiny.
"DAN, take me to the other gene on chromosome 10." The images around him blurred then re-formed. He was now inside the double helix looking along its fluorescent, multicolored length, traveling down an incandescent boulevard of genes. The nucleotide pairs of the second new gene were all around him along the double helix. He was
inside
one of the genes that made Christ different from other men. He felt a sense of genuine awe. But it was to the randomness of nature that he paid homage for creating this exception to its laws.
However, it was the third gene on chromosome 18 that really took his breath away. No wonder DAN had called it complex; it was hundreds of thousands of base pairs long--far longer than any he had seen before. He could only guess at what wonders its program coded for. His mind was suddenly filled with questions about how they were going to unlock these genes and harness their powers. Would they behave in the same way as usual genes? Could he use normal recombinant DNA technology to express the proteins coded by them in lab-controlled bacteria? Could he load them into a virus, and insert them directly into a patient--into Holly? So many questions. But they were
good
questions. Options. He now had material to work with. He could do something at last.
He suddenly realized that he'd been monopolizing the headset and removed it to give someone else a look. As usual his eyes took a moment to adapt to the real world, but he instantly sensed that the others were no longer crowding around the headset. Surprised, he turned and through unfocused eyes noticed they were grouped around someone standing on the other side of DAN. He felt his excitement turn to annoyance. It was understood that nobody apart from the Cana team was allowed into this section of the Mendel Suite. And it was especially important today. Now.