Platinum coat color locus in the deer mouse

Area of Science:

• Genetics
• Zoology
• Evolutionary Biology

Background:

• Coat color mutations are crucial for understanding genetic diversity and evolutionary processes in wild populations.
• The deer mouse (Peromyscus maniculatus) is a valuable model organism for studying mammalian genetics due to its diverse coat color variations.
• Previous research has identified several coat color loci in deer mice, including silver (si), albino (c), blonde (bl), brown (b), and agouti (a).

Purpose of the Study:

• To characterize the genetic basis of the platinum coat color mutation in Peromyscus maniculatus.
• To determine if the platinum trait represents a novel locus distinct from previously identified coat color genes.
• To investigate the recurrence and population dynamics of the platinum mutation.

Main Methods:

• Phenotypic observation of platinum deer mice, noting distinct pale coloration, light ears, and tail stripe.
• Genetic analysis to confirm the autosomal recessive nature of the platinum trait.
• Comparison of the platinum locus (pt) with known coat color loci (si, c, bl, b, a) in Peromyscus maniculatus.
• Assessment of mutation rates and selection pressures acting on the platinum phenotype in wild populations.

Main Results:

• The platinum coat color is an autosomal recessive trait, designated by the locus pt.
• The pt locus is genetically distinct from the si, c, bl, b, and a coat color loci.
• A phenotypically identical mutation, termed pewter, was identified as an independent recurrence of the platinum trait.
• The observed recovery rate of coat color mutations aligns with mutation rates balanced by strong negative selection against the recessive platinum phenotype.

Conclusions:

• The platinum (pt) locus represents a newly identified genetic determinant of coat color in deer mice.
• The independent recurrence of the platinum/pewter trait highlights the dynamic nature of mutation in wild populations.
• Strong selection against the recessive platinum phenotype plays a significant role in its population frequency, indicating an adaptive landscape favoring darker or wild-type coloration.