What is the term for a white rat with black eyes? - briefly
The appropriate designation is a black‑eyed white rat (commonly abbreviated BEW). It is a white‑coated animal that retains normal melanin in the eyes, distinguishing it from albino specimens.
What is the term for a white rat with black eyes? - in detail
A rat that displays a completely white fur coat while retaining normal, dark‑pigmented eyes is described as a “white‑coated, pigmented‑eye” specimen. In laboratory nomenclature this phenotype is often abbreviated as “W / p,” where “W” denotes the white coat allele and “p” indicates the presence of functional eye‑pigment genes. The animal is not albino; albinism results from a lack of melanin throughout the body, producing pink or reddish eyes.
The white coat arises from a mutation that suppresses pigment production in the skin and hair, but the mutation does not affect the melanocytes responsible for eye coloration. Consequently, the iris retains melanin, yielding the characteristic black or dark brown appearance.
Common laboratory strains that exemplify this phenotype include the Sprague‑Dawley and Wistar rats. Breeders select for the white‑coat, pigmented‑eye trait because it provides a uniform background for experimental procedures while preserving normal visual function.
Key points of the phenotype:
- Fur: completely white, lacking any pigment cells in the skin.
- Eyes: dark‑pigmented, normal visual acuity, typical iris coloration.
- Genetic notation: W / p (white coat with pigmented eyes).
- Distinction: differs from true albinism (white coat with red or pink eyes).
Understanding this terminology is essential for accurate record‑keeping in research, breeding programs, and veterinary care.