Mercers

Mercers are people who have both the Z and T viruses but not the C virus. They are also commonly called furries as they tend to involuntarily express animal traits from the food that they eat.

Basic Information

Genetics and Reproduction

From the T-virus, the somatic cells of gain a plasmid in their somatic cells which contains DNA that they can xenoexpress. From the Z-virus, Mercers are easily able to add to the contents of that plasmid, essentially performing Melding on the level of DNA. This is integration into the plasmid is possible because the Z-virus encodes for a restriction enzyme that does not cut human DNA but does cut the plasmid, allowing for this foreign integration.
It is this plasmid that gives male Mercers their infertility. Research shows that it does not separate correctly during meiosis, as it is inconsistently treated like a chromosome, leading to sperm that mismatch the number of chromosomes in an egg. Sperm without this extra DNA are lighter, so centrifuging ejaculate can increase the chance of success of IVF. Unfortunately, this plasmid is usually lighter than the X chromosome, meaning that the lightest sperm are disproportionately carrying a Y chromosome. So, when Mercers do procreate, if it was done via IVF, it is much more likely that the resulting child will be male.
The exact reason why Mercers are much better at using Xenoexpression to their advantage than XRAIs/Zedheads or Londoners is still being studied. It has been noted that female Mercers are able to hold onto DNA from foreign sources much longer than male Mercers, and to be able to hold more different types. This mechanism is unknown but is thought to be similar to how cis woman (including non-infected) absorb DNA as a protection against an immune reaction to the fetus during pregnancy to lower the risk of eclampsia. It would be incorrect to say that this only applies to cis women — there must be some horomonal element at play too, as it has been observed transwomen Mercers are also skilled in this department and are represented in the Transformation Troops (leading some of them to call themselves double trans).
To be frank, Mercers are capable of using their transformation abilities to, ahem, enhance the sexual experience. Recognizing their natural ability in this field, some have taken up sex work. More conservative members of society have now begun to associate them with "degeneracy." Licentia's bylaws strictly prohibit hate-motivated retaliation but as with all large societies some members still harbor reactionary ideals. For Mercers who live outside of Licentia, this stigma is yet another reason why life among uninfected is risky.

Dietary Needs and Habits

Mercers are in the somewhat unique situation where their components' cravings (meat and bones) are lessened. Like all Zeds, Mercers cannot survive on a vegan diet, but the average Mercer has a weaker craving for human flesh than the average XRAIs/Zedheads. Interestingly this does not hold true for Trifected — in fact, the handful of Trifected who were Mercers and then recieved the C-Virus last have largely reported that their cravings got worse.

Genetic Ancestor(s)

• tomenthoid
• zeitgabberim