# Whole-genome sequencing of CRFK and PG-4 cells to infer the phenotype of the original donor cats

## TL;DR

This study uses whole-genome sequencing to infer the coat and iris color of the original donor cats for two commonly used feline cell lines.

## Contribution

The paper provides the first detailed genetic and phenotypic characterization of the donor cats for CRFK and PG-4 cell lines.

## Key findings

- CRFK cells originated from a cat with long black fur and non-blue irises.
- PG-4 cells originated from a cat with long bicolored white and black fur and non-blue irises.
- Genes related to coat and iris color are expressed in multiple organs beyond skin and eyes.

## Abstract

Crandell-Rees Feline Kidney (CRFK; kidney-derived) cells and PG-4 cells (astrocyte-derived) have been in use and have been passaged for decades in laboratories worldwide; however, no detailed information on the genetic background of the donor individuals is available, particularly regarding phenotype characteristics such as coat and iris color.

We performed whole-genome sequencing of CRFK and PG-4 cells. We analyzed the resulting data to infer the phenotype of the individual from which the cells were derived, specifically for the coat color, coat length, coat pattern, and iris color. Our data suggested that CRFK cells originated from a cat with long black fur lacking stripes and with non-blue irises; PG-4 cells originated from a cat with long bicolored white and black fur without stripes, and with non-blue irises. Analysis of publicly available RNA-seq data confirmed that genes associated with coat phenotype and iris color are expressed in the skin and eyes, as well as in various other organs.

Variants of the genes affecting coat phenotype and iris color may influence physiological functions throughout the body. These results shed light on the previously unknown genetic background of commonly used feline cultured cells and the phenotype of the donor individuals. These findings may facilitate more accurate interpretation of data obtained from cultured feline cells and provide guidelines for developing cell lines with domestic cat genotypes exhibiting diverse phenotypes through genome editing. This will help to provide clarity regarding deafness in cats with white fur and blue irises and elucidate the effects of melanocyte destruction caused by KIT gene mutations on the nervous system and the influence of other coat-related factors in organs other than the skin or functions independent of coat formation.

The online version contains supplementary material available at 10.1186/s40575-026-00150-9.