She backed up to her left, then turned to the side and bowed deeply to all of the professors.

The next name was called. A voice responded.

Asakura returned to her seat with her degree, watching as her cla.s.smates' names were called.

Following the university's graduation ceremony, the Pharmaceuticals students had come back here to their school for a private a.s.sembly, where degrees were given to everyone anew. This was the day when the normally drab lecture hall overflowed with the beaming faces of graduates, all in their best suits. Asakura had chosen to wear traditional attire, lent to her by her mother.

As she rolled up her degree and placed it in its tube, a refreshing breeze caressed her cheek.

She felt overwhelmed with joy and gazed out the window.

The weather was clear and beautiful, plum tree buds already opening in the warm air.

The wind carried a pleasant scent.

The reality of getting her degree finally hit her. Having been hospitalized, she hardly performed any experiments for a good while but did manage to finish and present her thesis.

There was still a burn mark on one part of her body, but the more obvious scars on her face had been corrected through skin grafting.

Asakura gazed at her cla.s.smates and reminisced about her school days. She had been through more than she cared to think, but on the whole it was an enjoyable six years. These last three in particular, she was thankful to have found her motivation. She nodded once to herself, thinking how right she was to have chosen this path.

After the ceremony, they relocated to the course seminar room for a final get-together.

They all celebrated with some beer, then focused their attention on Ishihara, who said: "On behalf of all the staff, I wish to congratulate you all. Most of you will now move on to pharmaceutical companies or research inst.i.tutions. But no matter what path you choose, I believe that every one of you already possesses enough knowledge to go anywhere with nothing but the highest confidence. Even if you choose company work, I hope you will dedicate yourselves to making full practical use of all you've learned here and that you make significant contributions to our field. And I have no reason to doubt that you all will."

The graduates smiled brightly.

"And to all you seniors," the professor said, raising his voice, "the state pharmaceutical exams are coming up in approximately one week. I don't care how much you drink today, but starting tomorrow I want to see every nose in a book."

Everyone laughed at this. Even Asakura looked to her friends and snickered. The professor made this same joke every year, but it never missed.

"In any case, bottoms up!" Ishihara raised his gla.s.s.

"Bottoms up!"

At once, the room filled with noise and excited chatter. Flashes went off everywhere.

Everyone gathered for a group shot as well. More beer was brought out and hors d'oeuvres were added.

Asakura chatted with her friends, then mingled around to greet the various professors to whom she was so indebted. She felt lonely to be parting from these people, but at the same time everyone seemed so relieved to be moving on.

Asakura's sadness was comfortably placated by a mild tipsiness.

Halfway through the party, she ducked out quietly and went to the Biofunctional Pharmaceuticals office on the fifth floor.

Since everyone was downstairs, there was no one else there. She opened the door to the lab, a place where she had spent so much of her time over the past three years.

She looked inside, only to notice that a number of the machines had been left running.

Someone was probably doing a PCR, since the thermal cycler was on.

She stood in front of her desk and ran her fingers gently along its now empty surface.

Asakura had already brought her Mac back to her apartment and was finished with packing.

She was struck by how vast her desk seemed with nothing on it.

She glanced over at her bookrack, where the year's issues of Nature were being stored.

They had been purchased by the course and were normally kept in the seminar room.

Asakura was unsure why they had been moved here, but maybe they were remodeling the room and were taking advantage of the available s.p.a.ce left from her absence. She stared at the perfectly lined spines, then plucked one out from among them.

She flipped through it and opened to the articles section.

The article was written in English, under which the names Toshiaki Nagashima, Sachiko Asakura, and Mutsuo Ishihara were printed. It was Toshiaki's piece.

She gazed at the page. Her data was printed as diagrams, to which long footnotes were attached. The images somehow seemed to her the remarkable work of some other person.

She felt flattered.

It was only a short two-and-a-half page article. Even so, it was the pride of the Biofunctionals course.

But she had not truly appreciated it until now.

She would probably never have her name mentioned in Nature again. And her one time was thanks to Toshiaki.

If only Doctor Nagashima were still alive.

Asakura clutched the magazine to her chest.

Toshiaki's face appeared before her. At that moment, her eyes began to sting with unexpected tears. Surprised at herself, she wiped her cheeks, smudging her makeup. But the tears kept falling. She did not even shed a tear when she broke up with her boyfriends in high school. She tried laughing to mask her unusual outburst of emotion, but managed only a damp sigh. She sniffed and tried to smile away her sorrow.

She opened to the "NEWS AND VIEWS" section and turned to a piece of commentary.

Memories of the day she learned of Toshiaki's death came flooding back.

She'd read this short article when the magazine first came out, but had forgotten about it. While in the hospital, she learned in great detail from the police and cla.s.smates what Eve 1 had done. She knew that Eve l's mitochondria had rebelled, that the recipient girl was forced to give birth, that the child unexpectedly morphed between male and female, and that in the end Toshiaki and the new birth melted into one another and perished in flames. When Asakura first heard about this, she did not understand why the mitochondrial child had died.

But then, she remembered the theory presented in this article.

It had always been accepted that mitochondrial DNA was pa.s.sed through maternal heredity. Though male mitochondria entered an egg via the sperm which carried them, they did not multiply afterwards, and the mitochondria carried by the conceived child were once thought to have all been maternal. Genetic researchers accordingly a.n.a.lyzed mitochondrial DNA with this "matrilineal" rule in mind, and it indeed became a useful tool for theorizing the rate at which evolutionary processes occurred.

But in 1991, a certain research group announced some shocking results. When different species of mice were crossbred, it became clear that there was paternally transmitted mitochondrial DNA in their offspring. Though only a trace amount, its presence was unmistakable. The article undermined everything and was the subject of much attention.

Since then, other researchers debated about whether or not mitochondrial DNA was actually unis.e.xually inherited. Then, more recently, the problem had finally been clarified.

The results, in simple terms, were as follows: In instances of interbreeding among identical species, the father's mitochondrial DNA entered the egg via his sperm, but after a certain amount of time, it died out, presumably neutralized by the placenta. In other words, the father's mitochondrial DNA was ultimately not inherited by the birthed child. However, when different species were crossbred, the opposite was true. The offspring's mitochondrial DNA was found to be 56% paternal.

Asakura thought that probably Eve 1's sole intent in breeding with Toshiaki was to acquire his nucleus so that she could create a new species with it and her mitochondrial DNA. But while Eve 1 was being cultivated in the lab, it had developed into a non-human species. The mating of Eve l's egg cell with Toshiaki's sperm was essentially an interspeciary crossbreeding. Toshiaki's mitochondrial DNA grew inside the egg to drastic results.

Asakura skimmed through the Nature article. She had come back to it numerous times since leaving the hospital.

It was a summary of the hereditary pattern of mitochondrial DNA observed in a species of the blue mussel family. In the case of this species, the father's mitochondrial DNA was pa.s.sed on to children, but the method of transmission involved was found to be incredibly unique. Unlike humans and lab mice, males carried masculine mitochondrial DNA and females carried feminine mitochondrial DNA. When the two mated, something peculiar happened. Though the sperm contained male mitochondrial DNA and the egg contained female mitochondrial DNA, female offspring inherited genes only from the female mitochondrial DNA, while male offspring inherited an equal amount of genes from both. As the male offspring grew, the male mitochondrial DNA multiplied within it and ultimately established dominance. In other words, unlike with mice, what occurred with mussels was "uni-parental transmission." Female mitochondrial DNA was only inherited by female mussels, and male mitochondrial DNA only by males.

One explanation claimed this was a defense mechanism to combat the "selfish"

dispersion of mitochondria. Let us say there has been a single mutation in mitochondrial DNA in a single female mussel, a mutation that dramatically speeds up the rate of its DNA replication. It would begin to proliferate in the mussel and continue to do so in its children, driving out the original female mitochondrial DNA. If maternal mitochondrial DNA were transferred to both sons and daughters, this altered DNA would spread through future generations. But if female DNA were inherited only by female offspring, the altered DNA would only be transmitted through the daughter's lineage. The mutation would be better contained. Introducing Richard Dawkins' concept of the "selfish gene" into this discussion opens up an interesting vista.

Dawkins' basic idea is that "all that a gene wants is to leave copies of itself in as many descendants as possible." In the case of the mussels, we have three such selfish players, the nuclear DNA, male mitochondrial DNA, and female mitochondrial DNA. The mutated female mitochondrial DNA, wanting nothing more than to proliferate as much as possible, will replicate itself rapidly to pa.s.s itself on to as many descendants as possible. But the male mitochondrial DNA doesn't want to be exterminated and will try to obstruct the propagation of the mutant female mitochondrial DNA. Moreover, the nuclear genomes in the mussels might not favor mutations in mitochondria with which they've enjoyed a working symbiotic relationship. If mitochondria changed too quickly, the host's very survival could be threatened. The female mitochondrial DNA's selfishness is, in this way, at odds with the self-interest of the two other players.

This was perhaps why a mechanism had arisen to keep female mitochondrial DNA in check. Perhaps something similar had happened in the thing born from Eve 1. Asakura certainly thought so.

The fertilized egg had received "evolved" mitochondrial DNA from Eve 1, whereas from Toshiaki, "normal" mitochondrial DNA was transferred, even if in a miniscule amount.

But these two sets of genes coexisted in the new life form.

The mitochondria in Eve 1 undoubtedly believed they had facilitated evolution by their own power alone. In actuality, paternal mitochondrial DNA had also played a role in mitochondrial evolution, but Eve 1's mitochondria had failed to see this. Eve 1 had not counted on Toshiaki's normal mitochondria being inherited by their daughter.

The normal mitochondrial DNA transmitted into their child must surely have feared being utterly destroyed by the evolved DNA. The normal DNA's egotism, which wanted nothing more than to leave descendants, flatly opposed the agenda of Eve l's more advanced mitochondrial DNA. A violent battle ensued between the two sets of genes, eventually leading to their mutual destruction.

This was as good a guess as Asakura could make. No one would ever know the full truth. People's knowledge of mitochondria was still incredibly limited. Mitochondrial research was only just beginning.

Asakura closed the journal.

Why did the mitochondrial child have to melt into Toshiaki until it died? This was also a big riddle. But Asakura thought she had an intuitive understanding where this tragic end was concerned. After all, Toshiaki and the mitochondrial offspring were father and child...

"Hey, Asakura, what are you doing all alone up here?" came an unexpected voice. She turned around to see the familiar face of a fellow student, one year behind her, who had also been under Toshiaki's guidance.

He removed some Eppendorf tubes from the thermal cycler, solving the mystery of who had left the machines running.

"Everyone's been looking for you. I wish you had told someone you were coming here."

"Sorry about that. I just wanted to take one last look around before I left."

Asakura returned the issue of Nature to its shelf and smiled to cover the fact she had been crying.

The student placed his tubes into a refrigerator and was about to close the door when he remembered something.

"Oh, by the way, I found some of Doctor Nagashima's cells in deep freeze, but wasn't sure what to do with them. Would you mind taking a look?"

"Cancer cells?"

"No, I'm not sine what they are."

She followed him into the equipment room. As he opened the large freezer door, a white mist billowed into her face. The student pulled out a rack and looked inside.

"Here they are."

He showed her a number of blood serum vials.

The labels were frosted over. She rubbed them with her fingertip.

Toshiaki's handwriting.

She held her breath.

They were dated August of the year before and marked "Eve 1."

Her heart gave a thump.

"...Asakura?"

She forced a smile.

"Something wrong? You look like you've seen a ghost."

"It's nothing. Is this all you found?"

"These, too," he said, and showed her a bag filled with several dozen vials. Some were labeled simply "Eve," but there were also others numbered as "Eve 2" and "Eve 3."

She was speechless.

These cells were being preserved in preparation for primary culture. Though frozen now, if they returned to room temperature, they would begin propagating all over again.

A cold shiver ran along her spine.

"What are these? I'll take care of them if you want."

"No, it's okay. Let's just throw them out. Thanks for finding them for me. I'll go put them in the autoclave."

"I can do it for you."

"That's okay. Just leave it to me."

Asakura gathered the vials into the bag and tied it securely. She went to the Cultivation Room, her feet picking up speed along the way.

None of these could be left behind. She had to destroy them immediately.

She ran into the Cultivation Room and opened the lid to the autoclave.

She threw the bag into it and closed the lid tightly.

If she killed these, all that would never happen again.

She was sure of it.

Just then, the back of her neck tingled sharply.