A recessive coat color dilution in Dexter cattle attributed to a missense mutation in <i>SLC45A2</i>
Bibliographic record
Abstract
Three colors of Dexter cattle are currently recognized: black, red, and dun. In Dexters, dun is determined by a recessive genotype of TYRP1 (b/b) that dilutes an otherwise black animal (MC1R genotype ED/-); this variant does not impact red cattle. A subset of Dexters with dilute coat colors described as dark dun/chocolate (CD) or light dun/cream (CL) were identified. Although phenotypically similar to dun, they did not have the expected TYRP1 b/b genotype. Given relationships among the reported individuals, we hypothesized that a novel recessive genotype is causative of CD on a black background and CL on a red background. Whole-genome sequence was generated from four dilute Dexters (three CD and one CL), and one black calf of a CD dam. None of the cattle sequenced had the TYRP1 b/b genotype. The comparison of variants in the five Dexter cattle to those from 226 non-Dexter control cattle resulted in the identification of a missense variant in SLC45A2 (NC_037347.1: g.39790189A>C; XM_002696386.6: c.398A>C) that fit the proposed hypothesis. Sanger sequencing of additional Dexter cattle (n = 227) demonstrated complete segregation of the recessive genotype with the CD and CL phenotypes. The mutation, predicted to result in a substitution of glutamine with proline (XP_002696432.2: p.Gln133Pro) in a transmembrane helix was classified as deleterious by SIFT. Further supporting its implication, SLC45A2 is responsible for coat color dilutions and oculocutaneous albinism type IV in multiple species. Testing for the SLC45A2 variant can be a valuable resource for Dexter breeders interested in coat color.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".