Mi-spotted: a mutation in the mouse

Publisher Website
Google Scholar
Abstract
Mi-spotted (misp) is a new mutation in the mouse at the microphthalmia (mi) locus. It has no obvious visible effect in either the heterozygote (misp/+) or homozygote (misp/misp) and was discovered by virtue of its interaction with white (miwh). Mice of genotypemiwh/mispare pale yellow with white spots; yellow areas later become ‘sooty’ at the first moult.Though mice of genotypesa/a;misp/+ anda/a;misp/mispcannot be visibly distinguished from those ofa/a; +/+, the amount of tyrosine-2-C14incorporated in melanin in skins of 5-day-old mice of these genotypes differed. Assays of tyrosine incorporation were extended to include other non-agouti genotypes differing only at the microphthalmia locus. The amount of tyrosine incorporated was greatest in +/+ followed in order bymisp/+,misp/+,misp/misp,miwh/+,miwh/misp, andmiwh/miwh.Pigment granules were examined in club hairs of these same genotypes for different regions of the hair shaft. Hairs ofmisp/+,misp/misp, andmi/+ could not be distinguished from +/+ either in number, kind or arrangement of granules. Hairs ofmiwh/+ showed reduced cortical and medullary pigment, especially distally, which was even more pronounced in hairs ofmiwh/misp. Medullary granules ofmiwh/mispvaried greatly in size with a few large yellow-brown granules.

This publication has 12 references indexed in Scilit: