WikiBreeding & genetics
Family limits & lineage
How the family line sets the lowest and highest a foal can be.
Every pairing has family limits: the lowest and highest a foal of that pairing can ever be, stat by stat. They come from the two parents and their four parents. A foal can still beat both parents or fall below them, but never past what its family allows.
What the limits are
Each stat is a pair of genes (alleles), one from each parent; see Genetics & inheritance. A foal takes one allele from the sire and one from the dam, and that is always allowed. What the limits catch is mutation: the rare random nudge an allele can get as it is passed on. A mutation can never push an allele below the family’s floor or above its ceiling.
- Ceiling: the best allele either parent carries, plus some headroom. That headroom is how a line climbs, a little every generation.
- Floor: a little below the weakest allele either parent carries. A strong family holds it up.
- Centre: where the family sits. The parents count for two thirds, the grandparents for one third. Mutations lean back towards it.
By the numbers live from the rules
- Headroom above the best parent allele
- up to +40
- Headroom for a one-generation jump, at least
- +10
- Floor below the weakest parent allele, at most
- 40 points
- A strong family protects the floor down to
- its centre − 60
- Inbreeding lowers the floor by
- 1 point per 1% of inbreeding (COI)
- Mutation lean per 100 above the centre
- +6% more likely to hurt
The ceiling: how a line climbs
A foal’s allele can reach the best parent allele plus 40. That is the whole room a generation has to grow. If the parents have only just jumped well above their own parents, the line hasn’t proved itself yet and the headroom shrinks: every 5 points of jump costs a point of headroom, down to 10.
| Parents compared with grandparents | Highest allele a foal can carry | Headroom |
|---|---|---|
| Level with them | 640 | +40 |
| 50 higher | 630 | +30 |
| 100 higher | 620 | +20 |
| 150 higher | 610 | +10 |
| 200 higher | 610 | +10 |
The floor: what a good family protects
The floor sits at most 40 below the weakest parent allele. If the family’s centre is high, the floor can’t drop more than 60 below that centre, so a strong family keeps it close to the weakest parent allele. The floor never rises above that allele, so a foal can always inherit any gene its parents carry.
Inbreeding cuts through that protection: the floor drops a further point for every 1% of inbreeding (COI), whatever the family. See Inbreeding & kinship.
| Grandparents' alleles | Family centre | Floor | Floor at 12.5% COI |
|---|---|---|---|
| 400 | 533 | 560 | 548 |
| 600 | 600 | 560 | 548 |
| 700 | 633 | 573 | 561 |
| 800 | 667 | 600 | 588 |
Mutations lean towards the family
At no inbreeding, a mutation is as likely to help as to hurt. Inside a family, an allele already above the centre is more likely to be nudged down, and one below the centre more likely to be nudged up: 6% more (or less) chance to hurt for every 100 points away from the centre. That keeps a line together. Inbreeding adds its own push towards harmful mutations on top.
Established, rising or foundation
The breeding preview names the kind of line a pairing comes from, in words (it judges a “rising” line from what is public about the parents and grandparents):
| Tag | What it means |
|---|---|
| Established line | Parents and grandparents are of a level. The foal can land up to 40 above its best parent's genes; mutations lean back towards the family's level. |
| Rising line | The parents are well above their own parents: a one-generation jump. Less headroom above them, and mutations lean back towards the family. |
| Foundation stock | No grandparents on record: both parents are foundation horses, such as starters or pack foals. The limits come from the parents alone; breeding on from the foal builds a line. |
A worked example
The six horses at the top of this page are real genomes made by the game. Below is what familyRange says for a foal of the sire and dam, worked out when this page is built. Numbers are alleles (0 to 1000), not potentials.
| Stat | Sire's alleles | Dam's alleles | Centre | Floor | Ceiling |
|---|---|---|---|---|---|
| Speed | 725 / 296 | 680 / 700 | 576 | 296 | 750 |
| Stamina | 244 / 922 | 776 / 727 | 641 | 244 | 946 |
| Burst | 355 / 651 | 495 / 808 | 566 | 355 | 841 |
| Durability | 942 / 371 | 555 / 802 | 641 | 371 | 966 |
| Adaptability | 442 / 831 | 765 / 385 | 603 | 385 | 869 |
| Temperament | 642 / 558 | 219 / 921 | 582 | 219 | 959 |
Same parents, weaker grandparents
Swap the four grandparents for ordinary horses and the parents become a one-generation jump. The ceilings come down (less headroom), the floors hold, and the line counts as Rising line. Add inbreeding at half-sibling level instead and the floors drop.
| Stat | Ceiling (level family) | Ceiling (weaker family) | Floor (level family) | Floor (weaker family) | Floor (level family, 12.5% COI) |
|---|---|---|---|---|---|
| Speed | 750 | 735 | 296 | 296 | 284 |
| Stamina | 946 | 932 | 244 | 244 | 232 |
| Burst | 841 | 821 | 355 | 355 | 343 |
| Durability | 966 | 952 | 371 | 371 | 359 |
| Adaptability | 869 | 849 | 385 | 385 | 373 |
| Temperament | 959 | 939 | 219 | 219 | 207 |
What the rules give for this example live from the rules
- Established line: lowest to highest possible
- 380 (E) to 810 (A)
- Rising line: lowest to highest possible
- 380 (E) to 803 (A)
- Foundation stock (no grandparents): lowest to highest possible
- 380 to 812
- Middle 80% of foals (any family)
- 517 to 669
Reading the preview
On the breeding screen, the preview names the line (established, rising or foundation) in a sentence under the outlook. It shows no limits or ranges as numbers: the numbers on this page are the rules at work on example horses. The preview is worked out only from what is public about the two horses, so it can’t give away their hidden genes, and the real foal is a surprise.