Misty (m) affects growth traits.
The misty (m) coat color mutation is commonly maintained in linkage disequilibrium with the obesity mutation diabetes (Leprdb) to serve as a marker for Leprdb genotype. Comparisons among Leprdb genotypes are made under the untested assumption that m has no effects on traits under investigation. We tested this assumption in a population segregating m in the absence of db. Analysis of growth curves revealed that m/m mice are smaller than M/M mice by the 2nd wk of life and remain smaller through the 5th wk of life. Analysis of variance of three traits measured at 35 days of age revealed that m/m mice are 8% shorter than M/M mice, weigh 15% less, and have 21% less inguinal adipose mass. These results indicate that m affects growth traits. Therefore, when m and Leprdb segregate in the same cross, interpretation of their effects is confounded by linkage. More accurate estimates of Leprdb genotype effects can be made by removing m from populations segregating Leprdb and using a direct assay to measure Leprdb genotype.
Pennington Biomedical Research Center, Baton Rouge, Louisiana 70808, USA.
G E
GE
Truett
R J
RJ
Tempelman
J A
JA
Walker
J K
JK
Wilson
D000375:Aging; D000704:Analysis of Variance; D000818:Animals; D001835:Body Weight / Q000235:genetics; D003433:Crosses, Genetic; D003920:Diabetes Mellitus / Q000235:genetics*; D005260:Female; D005819:Genetic Markers; D005838:Genotype; D006128:Growth / Q000235:genetics*; D006200:Hair Color / Q000235:genetics*; D015810:Linkage Disequilibrium; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D009765:Obesity; D012727:Sex Characteristics
D005819:Genetic Markers