Heredity of Mystaran Half-Elves
by David KnottThe "Elves of Alfheim" gazetteer strongly suggests that the traits of "elvishness" or "humanness" are passed down on the same chromosomes that determine sex. For a normal mating between two humans, the results are as follows:
Xh Yh x Xh Xh = Half Xh Yh (male human) and half Xh Xh (female human)
Similarly, a normal mating between two elves has the following results:
Xe Ye x Xe Xe = Half Xe Ye (male elf) and half Xe Xe (female elf)
If a human mates with an elf without Immortal intervention, then we get the results described in the "Elves of Alfheim" gazetteer. First, let us consider the case of a mating between a male elf and a female human:
Xe Ye x Xh Xh = Half Xh Xe (female with mostly human characteristics) and half Xh Ye (stillborn male -- apparently this combination is not viable)
If a male human mates with a female elf, we get:
Xh Yh x Xe Xe = Half Xe Xh (female with mostly human characteristics) and half Xe Yh (male with mostly elven characteristics)
The surviving offspring of these matings introduce two new combinations (Xe Xh and Xe Yh) who may mate with humans, elves, or each other to produce viable offspring. The results of these matings are as follows:
Xe Xh x Xh Yh = Quarter Xe Xh (female with mostly human characteristics) and quarter Xh Xh (female human) and quarter Xe Yh (male with mostly elven characteristics) and quarter Xh Yh (male human)
Xe Xh x Xe Ye = Quarter Xe Xe (female elf) and quarter Xh Xe (female with mostly human characteristics) and quarter Xe Ye (male elf) and quarter Xh Ye (stillborn male)
Xe Yh x Xh Xh = Half Xh Xe (female with mostly human characteristics) and half Xh Yh (female human)
Xe Yh x Xe Ye = Half Xe Xe (female elf) and half Xe Yh (male with mostly elven characteristics)
Xe Yh x Xe Xh = Quarter Xe Xe (female elf) and quarter Xe Xh (female with mostly human characteristics) and quarter Xe Yh (male with mostly elven characteristics) and quarter Xh Yh (male human)
Engledoc Dewsap's mother was an Xe Xh female, while his father was the Xh Yh offspring of an Xe Yh x Xe Xh mating -- which makes Engledoc an Xe Yh.
Immortal intervention has created two sorts of half-elf. On the Savage Coast, the Immortals homogenised and made dominant the characteristics of a half-elf, resulting in the combinations of X* X* for females and X* Y* for males. The "*" characteristic is dominant and causes any offspring with that characteristic on either sex chromosome to be a half-elf. Only if this characteristic is missing from both sex chromosomes can the offspring express full elvish or human characteristics.
In Davania the Immortal Mealiden created a race of Amazon warriors to protect his elven followers. These Amazons had the XA XA chromosome combination and normally mated with male elves, as follows:
XA XA x Xe Ye = Half XA Xe (female Amazons) and half XA Ye (males who miscarry before the mother knows she is pregnant)
Next generation:
XA Xe x Xe Ye = Quarter XA Xe (female Amazons) and quarter Xe Xe (female elves) and quarter Xa Ye (males who are miscarried as before) and quarter Xe Ye (male elves) M
ale elven offspring are turned over to their fathers at birth, while female elven offspring are turned over when their slow growth makes it apparent that they are elves and not humans or Amazons.
Amazon matings with male humans have the following results:
XA XA x Xh Yh = Half XA Xh (female Amazons) and half XA Yh (males who miscarry early in pregnancy)
Next generation:
XA Xh x Xh Yh = Quarter XA Xh (female Amazons) and quarter Xh Xh (female humans) and quarter XA Yh (miscarried males) and quarter Xh Yh (male humans)
Male human offspring are turned over to their fathers at birth, while female human offspring are brought up as though they were real Amazons. The most likely human-Amazon mating would produce the following results:
XA Xe x Xh Yh = Quarter XA Xh (female Amazons) and quarter Xe Xh (female humans carrying elven characteristics) and quarter XA Yh (miscarried males) and quarter Xe Yh (male elves)
The male elven offspring are turned over to their fathers, who probably prove unequal to the task of raising them. The female human offspring are brought up as though they were real Amazons.
Crossing human-bred Amazons back with male elves results in the following offspring:
XA Xh x Xe Ye = Quarter XA Xe (female Amazons) and quarter Xh Xe (female humans carrying elven characteristics) and quarter XA Ye (miscarried males) and quarter Xh Ye (stillborn males)
Those Amazons who lack the "XA" chromosome are physically weaker than "real" Amazons and usually do not survive or are prevented from mating by other Amazons -- they are trained as mages (if they are have any elven ancestry) or as clerics (otherwise) and are sworn to vows of chastity and celibacy in either case.
Summary:
"A" chromosomes are incompatible with "Y" chromosomes and causes miscarriage very early in pregnancy. In combination with any other "X" chromosome they produce strong and viable Amazon (human) warriors.
"*" chromosomes dominate all other chromosomes and result in true half-elves. In the extremely unlikely event that a girl child is born with the "XA X*" combination, she is a female Amazon warrior who shares the best characteristics of a human and a half-elf.
The Xh Ye combination is lethal and results in a stillbirth.
The Xe Yh combination results in a male offspring who looks like a half-elf but has mostly elven characteristics.
The Xe Xh combination results in a female offspring who looks like a half-elf but has mostly human characteristics.
Characters of mixed ancestry who lose all elven or
human traits from their sex chromosomes may show physical signs of
their mixed ancestry but for most purposes should be treated as
elves or humans as appropriate.