Yesterday's Kin Read Free Page B

lounge chairs and gold-braided officers.
    A submarine. Well, that made sense, if plans had been put in place to get to the Embassy unobserved by press, tourists, and nut jobs who would blow up the alien base if they could. The Denebs must have agreed to some sort of landing place or entryway, which meant this meeting had been talked of, planned for, long before today. Today was just the moment the aliens had decided to put the plan into practice. Why? Why so hastily?
    “Dr. Jenner,” Desai said, “in the short time we have here, please explain your scientific findings to us.”
    None of them sat in the lounge chairs. They stood in a circle around Marianne, who felt none of the desire to toy with them as she had with Dr. Curtis at the college. Where were her words going, besides this cramped, luxurious submarine? Was the president of the United States listening, packed into the situation room with whoever else belonged there?
    “My paper is nothing startling, Mr. Secretary-General, which is why this is all baffling to me. In simple terms—” she tried to not be distracted by the murmuring of the two translators into their mouthpieces “—all humans alive today are the descendants of one woman who lived about 150,000 years ago. We know this because of mitochondrial DNA, which is not the DNA from the nucleus of the cell but separate DNA found in small organelles called mitochondria. Mitochondria, which exist in every cell of your body, are the powerhouses of the cell, producing energy for cellular functions. Mitochondrial DNA does not undergo recombination and is not found in a sperm cell after it reaches the egg. So the mitochondrial DNA is passed down unchanged from a mother to all her children.”
    Marianne paused, wondering how to explain this simply, but without condescension. “Mitochondrial DNA mutates at a steady rate, about one mutation every 10,000 years in a section called ‘the control region,’ and about once every 3,500 years in the mitochondrial DNA as a whole. By tracing the number and type of mutations in contemporary humans, we can construct a tree of descent: which group descended from which female ancestor.
    “Evolutionary biologists have identified thirty of these haplogroups. I found a new one, L7, by sequencing and comparing DNA samples with a standard human mitochondrial sample, known as the revised Cambridge Reference Sequence.”
    “How did you know where to look for this new group?”
    “I didn’t. I came across the first sample by chance and then sampled her relatives.”
    “Is it very different, then, from the others?”
    “No,” Marianne said. “It’s just a branch of the L haplogroup.”
    “Why wasn’t it discovered before?”
    “It seems to be rare. The line must have mostly died out over time. It’s a very old line, one of the first divergences from Mitochondrial Eve.”
    “So there is nothing remarkable about your finding?”
    “Not in the least. There may even be more haplogroups out there that we just haven’t discovered yet.” She felt a perfect fool. They all looked at her as if expecting answers—Look! A blinding scientific light illuminate all!—and she had none. She was a workman scientist who had delivered a workmanlike job of fairly routine haplotyping.
    “Sir, we have arrived,” said a junior officer. Marianne saw that his dress blues were buttoned wrong. They must have been donned in great haste. The tiny, human mishap made her feel better.
    Desai drew a deep, audible breath. Even he, who had lived through war and revolution, was nervous. Commands flew through the air from invisible people. The submarine door opened.
    Marianne stepped out into the alien ship.
    NOAH
    “Where’s Mom? Did you call her?” Elizabeth demanded.
    “Not yet,” Noah said.
    “Does she even know you’re in New York?”
    “Not yet.” He wanted to tell his sister to stop hammering at him, but he was her guest and so he couldn’t. Not that he’d ever been able to stand up to