Seveneves - Страница 108

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“That’s harder,” Moira admitted. “Synthesizing a Y chromosome is no joke. My prediction is that the first set of babies — perhaps the first few sets of them — will all be female. Because we simply need to get the population up. During that time I can be working on the Y chromosome problem. Later on, I hope that some little boys will result.”

“But these little girls — and later the boys — will still be made out of our own DNA?” Ivy asked.

“Yes.”

“So they’ll be quite similar to us genetically.”

“If I do nothing about it,” Moira said, “they’ll be like sisters. Perhaps even more similar than that implies. But there are a few tricks that I can use to create a wider range of genotypes out of the same source material. Perhaps they’ll be more like cousins. I don’t know, it’s never been tried.”

“Are we talking about the inbreeding problem? It sounds like it,” Dinah said.

“Loss of heterozygosity. Yes. I happen to know something about it. It’s why I was chosen as a member of the General Population.”

“Because of your work on black-footed ferrets and so on,” Ivy said.

“Yes. This is a closely analogous problem. But the point I would like you all to keep in mind is that we solved that problem in the case of the black-footed ferrets and we are going to solve it again.”

She said it with force and confidence that silenced the others for a few moments and left them looking at her for more.

Moira went on. “I think we all have at least an intuitive understanding of this, yes?”

That one was aimed at Julia, who looked mildly peeved, and bit off the following: “My daughter had Down syndrome. That is all I will say.”

Moira acknowledged it with a nod, then went on: “Everyone has some genetic defects. When you are breeding more or less randomly within a large population, there’s a tendency for those errors to be swamped by the law of averages. Everything sort of works out. But when two people sharing the same defect mate, their offspring is likely to have that defect as well, and over time we see the usual unpleasantness that we all associate in our minds with inbreeding.”

“So,” Luisa said, “if we follow the plan you have laid out, and begin, a few years down the road, with seven groups of what amount to siblings or cousins—”

“It’s not enough heterozygosity, to answer your question,” Moira said. “If you have a genetic predisposition to any disease, for example—”

“Alpha-thalassemia runs in my family,” Ivy said.

“That’s a fine example,” Moira returned. “As it happens, Old Earth compiled vast databases on such things before its destruction. All of which are in there now.” She gestured in the direction of her lab. “We have a very good idea which defects, on which chromosomes, are responsible for alpha-thalassemia. If you supply me with an ovum, I can find those defects and I can fix them before we begin parthenogenesis. Your offspring will be free of that defect. Barring some random future mutation, it’ll never return.”

Dinah raised her hand. “My brother was a carrier of cystic fibrosis. I haven’t been tested.”

Julia raised hers. “Three of my aunts died of the same form of breast cancer. I’ve been tested. I know I carry that defect as well.”

“The same answer applies in all of these cases,” Moira said. “If there’s a genetic test for it, then it means, by definition, that we know which defects are responsible for it. And knowing that, we can perform a repair.”

A new voice joined the conversation. “How about bipolar disorder?”

Everyone looked at Aïda.

She would live out the rest of her life, and go to meet her maker, without having a friend, or even a friendly conversation. So, no one was in a receptive frame of mind about her question. But the mere fact that she’d asked it suggested a level of introspection they hadn’t seen from her before. Moira considered it.

“I would have to do some research. I think that it does run in families to some extent. To the extent that it can be traced to particular locations on particular chromosomes, it can be treated like any other disease,” Moira said.

“Do you believe it should be?” Aïda asked.

Everyone looked automatically at Luisa, who nodded. “We are long past the point of thinking of mental illnesses as somehow a lesser kind of disease than physical. Such disorders should, in my opinion, be addressed in just the same way.”

“Do you believe it must be?”

Luisa colored slightly. “What is the point of these questions, Aïda?”

“I have done research on it,” Aïda said. “Some say that bipolarity is a useful adaptation. When things are bad, you become depressed, retreat, conserve energy. When things are good, you spring into action with great energy.”

“And your point is. .”

“Will you treat this condition in my offspring against my will? What if I want to have a lot of little bipolar kids?”

In the flustered silence that followed, Camila spoke. “What about aggression?”

Everyone turned to look at her, as if unsure they had heard her correctly.

“I’m serious,” she said. She looked toward Aïda. “I don’t mean to trivialize the suffering that your condition causes. But over the course of history, aggression has caused a far larger amount of pain and death than bipolar disorder or whatever. As long as we are fixing those aspects of the human psyche that lead to suffering, should we not eliminate the tendency to aggressive behavior?”

“That’s different,” Moira began. But she was interrupted by Dinah.

“Hold on a sec,” Dinah said. “I’m aggressive. I always have been. I was on track to be an Olympic soccer player! That’s the only way I’ve ever been able to amount to anything — by channeling my aggression into doing things.” She nodded across the table at Tekla. “Hell, look at her! How many times has she saved our asses by being aggressive?”

Tekla nodded. “Yes. Dinah saved me by taking aggressive action against rules of space station. Problem is not aggression. It is lack of discipline. A person can be aggressive”—she nodded at Dinah—“and still be constructive in society if she controls her passions.” And she threw a significant glare at Aïda, who let out a little snort and looked away.

“So you’re suggesting we breed people for discipline and self-control?” Ivy asked. “I’m not sure if I follow.”

“I believe that Camila was merely saying that certain personality types, taken to an unhealthy extreme, are as bad as diagnosable mental illnesses per se. If not worse,” Julia said.

“I don’t want you to speak for me,” Camila said. “Please do not speak for me anymore, Julia.”

“I am merely trying to be helpful,” Julia said. But where the old J.B.F. would have said it reproachfully, the new one merely seemed exhausted.

Dinah broke in. “Well, what I am trying to say is that I don’t appreciate being labeled as a genetic freak that needs to be eradicated from the human future.”

“No one would say that of you, Dinah,” Ivy said. “Camila’s talking about the knuckle draggers who tried to kill her for wanting an education.”

“And what is your opinion?” Tekla asked Ivy.

“Similar to yours. Aggression is fine. It needs to be controlled. Directed. But the way to do that is through intelligence. Rational thought.”

That elicited a cackle from Aïda. “Oh, sorry,” she said. “I was thinking about the Swarm. Eight hundred people all carefully hand-selected for intelligence and rational thought. In the end, all we could think about was how they tasted.”

“None of us ate each other,” Ivy said.

“But you thought about it,” Aïda said with a smile.

Dinah slammed her palm hard on the table. She sat still for a moment with her eyes closed tight, then stood up and walked out of the room.

“I guess she is not disciplined or intelligent enough to control her aggression!” Aïda cracked.

“It is a form of self-discipline,” Tekla said. “So that she would not kill you. You see, Aïda, thinking about doing such things and doing are different. This is why greater discipline is a requirement.”

“Sweetie, what do you mean when you speak of discipline?” Moira asked. “I’m just trying to cash that word out in terms of genetics. I can find a genetic marker for cystic fibrosis. I’m not sure if the same is true of discipline.”

“Some races are disciplined. Is fact,” Tekla said. “Japanese are more disciplined than. . Italians.”

She gave Aïda a stare that would have frozen most people to their chairs, but Aïda just threw her head back and laughed exultantly. “You are forgetting the Roman legions, but please go on.”

“Men are more disciplined than women. Is just fact. So there must be genes for it.”

This produced yet another silence, eventually broken by Luisa: “I’m seeing a side of you I didn’t know about, Tekla.”

“Call me bad, call me racist if you want. I know what you will say: That it is all training. It is all culture. I disagree. If you do not feel pain, you do not respond to pain. And hormones.”

“What about hormones, lover?” Moira asked. Her affection for Tekla was obvious, and took some of the tension out of the room.

“We all know that when hormones are a certain way, emotions have big impact. Other times, not so much. This is genetic.”

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