Doctor Mann was born in 1971 under the name Ayuko Matsumori to Doctor Matsumori (her Chinese father) and Doctor Mastumori (her Japanese mother). She grew up with horrible allergies, leading her father to run constant tests on her with hopes of improving her health. An emotional distant child, Mann grew up to become a better geneticist than her father and scorns him for his rejection of her upon coming out to him as a lesbian.
After graduating from UC Berkley, she took on a job teaching at Harvard University. Shortly before the plague Doctor Mann heard of her father's attempts to clone humans and, as a way to further spite him, starts the process of cloning herself. Enlisting the aide of a student, primarily for prenatal care, she impregnated herself with her own clone. This clone died in childbirth at the moment the plague hit.
As the top surviving scientist in her field with knowledge of cloning, Yorick and Agent 355 set out to enlist the help of Doctor Mann in repopulating the now man-free world, as well as study Yorick and Ampersand to determine how they managed to survive. Mann first meets up with Yorick and 355 in Boston. Shortly thereafter her lab is burned to the ground by the Israelis forcing the three to travel across the country to her back-up lab in San Francisco.
Arriving in San Francisco, after a long series of exploits, Mann sets to work studying Yorick and Ampersand with hopes of discovering the key to their immunity to the disease that wiped out all males beside the two. The answer? Bacteria located in Ampersand's gallbladder, transferred to Yorick viva contact with Ampersand's feces.
Unfortunately just as soon as this breakthrough is discovered a new challenge comes as Toyota [sent by Allison's father] appears and kidnaps Ampersand. With the monkey possibly now the only key to the survival of any possible future males on Earth the three must now set out after Toyota. A clue sends them to japan. When on board the smuggler ship The Whale, Allison meets Rose, a woman who turns out to be a spy for the Australian navy, and later Allison's girlfriend.
When they arrive in Japan, Thinking they are intruders, Rose is stabbed by Allison's mother. Through this Mann is ironically reunited with her mother [Mann's mother then performs surgery to close Rose's wounds] they are then quickly separated once more as Toyota, kidnaps Mann's mother, demanding Ampersand in trade, the monkey having escaped her custody while traveling. Though at first Mann keeps this event a secret from her fellow travelers it is revealed as they travel to Hong Kong in search of research conducted by the one and only Doctor Matsumori, Mann's father.
Things get more complex as they find Doctor Matsumori not only alive, but with a deep understanding of the cause of the plague. Cloning. According to him, man was once a necessary evil on earth kept in existence only for the sake of reproduction. The moment a child, through his mistress Doctor Ming, was born without the assistance of man, it being a clone, nature took over and wiped the now unnecessary evil off the face of the earth. His answer now was to kill the last men on earth and leave it to the women. Mann then has to kill her father so he cannot kill Yorick and Ampersand. meanwhile 355 takes care of Toyota.
Now with a lab made for cloning, Doctor Mann continues her research, along with Rose, who agrees to carry a clone of Yorick for Allison. After they go their separate ways Yorick and 355 set out in search of Yorick's long lost love Beth.