Natural gene / health
Megaesophagus
A slack gullet that will not push milk down. The foal chokes on what it swallows and inhales the rest.
Crossing two of them
Born, and then lost
Lethal at birth, so the foal really is born: it gets a name, a record and a place in the family tree, and then dies over a few seconds with a chat line naming what took it.
That is deliberate. A pairing that silently produced nothing would teach a player nothing about the two horses they just bred, and the whole value of a recessive lethal is that it tells you something about both parents at once. The mechanics of the death are on the trait system page.
Its gene carrot
There is none. A disorder locus sets hasGeneCarrot() false —
forcing one onto somebody’s line is hostile — and
SpliceSafety keeps it out of the random splice as well, derived from
the fact that it declares a non-informational Condition rather than
from any hand-written list.
- Gene key
- horsegenetics.megaesophagus
- Priority
- 101
- Alleles
- meg N
- Outcomes
- wild,
megaesophagus-carrier,megaesophagus - Coat effect
- none — every outcome is a wild type
- Default allele
- N
- Wild population
- 1.7% of founders carry one copy; none carries two
- Founder draws
- 1 × nextFloat()
- Catalogue entries
- 1 — it never changes what a horse looks like
Every combination of this gene is an expression
marked wildType. That reads oddly for a gene that can kill a foal,
and it is exactly right: wildType means changes nothing about
the coat. Because none of the non-coat genes paints,
Gene.affectsCoat() is false for all of them, they are left out of a
horse’s texture key, and the whole locus collapses into one catalogue
entry. What the gene actually does travels on
the trait system instead.
The combination table
| combination | outcome | effect |
|---|---|---|
N/N | wild type | nothing |
meg/N | megaesophagus-carrier | nothing — a completely normal horse |
meg/meg | megaesophagus | −14 health, −0.03 speed, −0.10 jump — lethal at birth |
The gentlest of the lethals, on the numbers
Because the failure is mechanical rather than systemic: there is nothing
wrong with the foal except that it cannot eat. It carries the smallest heart
reduction and the smallest movement penalty of any lethal here, and dies anyway
— which is worth noticing, because it makes plain that the heart number is
flavour on a lethal locus and the Severity is what actually decides.
No confirmed causal variant
Like CVM, this is a breed condition that is clearly heritable and has no agreed single gene behind it, so it is keyed on the condition rather than on a gene symbol and the simplification to one recessive locus is the mod’s own. See that page for the reasoning, which is the same reasoning.
The founder table lists only the clear horse and the carrier. A wild-caught horse is an adult that survived, so it can carry this and never have it, and the homozygote’s weight is simply absent from the table. The only way to produce an affected foal is to breed two carriers — which is the whole design: it is what makes a pedigree worth keeping, and what turns the carrier wording in the info panel from decoration into the difference between a breeding programme and a lottery.
common/genetics/genes/MegaesophagusGene.java