Chapter 349

After the public class ended, Harry noticed most of the children were rushing eagerly toward the cafeteria, while Clara calmly gathered her lesson materials on the podium.

"Uh, Professor Clara?" Harry stepped forward and asked, "Would you have a moment to answer some questions about genetics?"

"Of course, Snape told me about this," Clara glanced at Ron beside Harry, then chose her words carefully, "This is a difficult case of paternal half-sibling paternity testing, inherently unreliable."

"It's fine, Ron knows everything," Harry noticed the subtle gesture.

"Oh, great," Clara nodded, "I actually participated in the Doctor Project—in other words, I know everything too."

Harry blinked.

"In this case," Clara smiled, then picked up a piece of chalk and rewrote on the blackboard, "we need to determine the kinship between half-siblings sharing the same father. First, we note that sex chromosomes cannot be used for identification, because the father must pass the Y chromosome to the son and the X chromosome to the daughter."

Harry nodded—he knew this.

"We can only analyze through autosomal comparison, but this raises a problem: under Voldemort's death, we cannot determine his genotype." She wrote two rows of letters, then circled one randomly on the left and one on the right in each row, "By comparing Delphi and Bellatrix's DNA, we can identify half of Voldemort's genes—but that half is completely random. All twenty-two autosomes might share half each, or none at all. If we find, say, four to six matching segments, we cannot accurately—or even approximately—determine whether they are siblings, because such similarity also occurs among many cousins."

"I've reviewed some papers. All credible existing cases relied on the mother plus siblings to infer the father's full or near-complete genotype—but now we only have Delphi. We cannot determine the father's genotype at all."

"But at least we can still determine blood relation, right?" Harry asked. "We can prove they're related, then just prove Voldemort had no other relatives?"

"Scientifically, yes—we can prove they're at least some kind of close relative, even if not siblings," Clara nodded, "but now there's a more troubling issue: the magical ritual."

Harry glanced around, then whispered, "You mean the ritual Voldemort used to resurrect himself?"

"Yes. Not just us—Death Eaters know it. The White House knows it too." Clara tapped the desk. "Clearly, magic doesn't affect anything outside your awareness. In other words, during the body's reconstruction, since Voldemort had no concept of genes, he didn't alter them. Therefore, his body's genome consists of three parts: yours, your father's, and the Death Eater who contributed flesh—Rodolphus Lestrange."

Harry swallowed.

"Under these conditions, comparing your DNA with the new Voldemort's should reveal at least one-third of chromosomes identical. If we factor in Saruman's case—that is, a one-in-four chance you and Voldemort inherited identical genes from your father—but Voldemort's father only accounts for one-third of the new Voldemort's genome, meaning your difference is only one-twelfth."

"But Voldemort fathered Delphi only after his resurrection, right?" Ron, still half-dazed, asked a crucial question.

"Exactly." Clara struck the blackboard firmly. "That means Delphi carries at least one-third of her genes from Harry—whether pure-blood Harry or Harry with Dark Lord blood."

"And if we want to prove Saruman's existence, we must prove that extra one-twelfth," Clara shook her head. "But that refers to the similarity between Saruman and Voldemort—translated to Delphi, it becomes one twenty-fourth. The probability of difference is already high; it proves nothing."

"But if we detect that one twenty-fourth, wouldn't that prove it?" Ron asked.

"The problem is, we have no idea how genes combined during the magical resurrection. Perhaps each party contributed full pairs of seven or eight chromosomes—or perhaps fourteen or fifteen chromosomes each. In the most extreme case, Harry and Delphi could be completely unrelated—or share over half their chromosomes."

"We can't prove this statistically—the sample size is too small, the differences nearly nonexistent." Clara spread her hands. "In other words, because of this resurrection ritual, we cannot prove any conclusion: unless a low-probability event occurs—more than eighteen chromosomes match—then we can confirm they are paternal half-siblings. Otherwise, even if they share zero similarity, we can't definitively deny kinship."

"But you said genes have billions of base pairs—how is the sample size lacking?" Ron asked, dazed.

"Because I've been talking only about specific marker sites on chromosomes!" Clara tapped his forehead in exasperation. "If you calculated all base pairs, you'd share over ninety percent similarity with a mandrill!"

"Maybe there's still a way," Harry murmured, stroking his chin. "I originally planned to use Ron and Ginny's hair for testing—they should share at least eighteen matching chromosome pairs, right?"

"No, Ron and Ginny's similarity is also uncertain. In the extreme case, if Ron took all left halves from his father's chromosomes and Ginny took all right halves," Clara drew a vertical line between the two rows of letters, "and in their mother's genes they happened to be exact opposites—they could be completely unrelated siblings. The probability is tiny, but not impossible."

"Then take multiple sibling pairs," Harry proposed a new idea. "Choose the one most suitable for us?"

"That brings up conditional probability. We calculated the chance of Harry and Delphi matching over eighteen chromosomes is extremely low. So if that result appears," Clara shrugged, "the White House will suspect fraud before they consider the low-probability event."

"The worst part is, the White House seems unwilling to see unification between the British magical and non-magical worlds—they're actively obstructing this." Clara lowered her voice. "The CIA has highly skilled agents in both worlds. If they investigate properly, they'll easily detect fraud. If you test honestly, you'll just keep arguing. But if fraud is exposed, things turn even worse."

"Just give your hair to Snape honestly," Clara suggested mysteriously. "Leave it to the adults. You know Snape has already turned Holf, the one in charge of testing."

Harry gave an awkward smile and scratched his head, changing the subject: "You know way more than I imagined."

"Of course. I deeply participated in the Doctor Project—I met nearly all the Doctors. Snape concluded I was trustworthy." Clara's face softened with nostalgia. "The Doctors foresaw fate—we would never defy him."

"Fate… you used 'he,' not 'it'?" Harry frowned. "I don't know if I should ask, but time is frozen now, Death is cut off—can you tell me how the Doctors understood the relationship between fate, time, and Death?"

"You're right—we used to avoid speaking of this, fearing Death's wrath." Clara shook her head gently. "But now I still can't tell you—only you, because you're entangled in too much fate… not even Ron."

"After Death was cut off, ordinary wizards gained more autonomy—but you, Harry, you're the one favored by fate. Telling you might trigger unimaginable consequences—" Clara bit her lip. "Without Death, the timeline we live in is far more fragile than you imagine."

After a brief silence, Clara cleared her throat awkwardly. "Yes, I shouldn't stay near you too long. I'm preparing to return to Beauxbatons."

"Why?" Harry looked utterly confused.

"If Death still watches you, He would warn—or mislead—those of us who glimpse fate, to prevent accidents. But now, I fear I might make things worse." She trailed off, unsaid words hanging.

"You'll miss lunch—hurry to the cafeteria."

Harry checked his watch—yes, the conversation had taken too long. Seeing Clara's guarded expression, Harry remembered Neville's discovery: perhaps the Doctors hadn't placed everything inside the TARDIS. Perhaps something—a conclusion—was hidden somewhere in the Department of Mysteries.

And Dumbledore's hint to Neville might have been meant to bypass Harry—or to evade Death's gaze… Harry

"She's right—I'm starving." He took Harry's hand and hurried out of the classroom.

"Run, little clever one, run," Clara whispered.