Glk: a locus controlling galactokinase activity in the mouse.

Area of Science:

• Genetics
• Biochemistry
• Mouse models

Background:

• Inbred mouse strains show significant variation in whole blood galactokinase (GALK) activity.
• GALK activity levels cluster into two distinct classes, with one class exhibiting approximately double the activity of the other.
• F1 hybrids between high and low GALK activity strains display intermediate activity levels.

Purpose of the Study:

• To investigate the genetic basis of galactokinase (GALK) activity variation in mice.
• To identify the inheritance pattern and chromosomal location of the GALK locus.

Main Methods:

• Development of two sets of recombinant inbred (RI) mouse lines from crosses between high and low GALK activity strains.
• Analysis of GALK activity segregation within RI lines to determine inheritance patterns.
• Comparison of GALK locus strain distribution patterns with known esterase-3 (Es-3) alleles.

Main Results:

• RI lines segregated for GALK activity, indicating single gene inheritance.
• The galactokinase locus was designated Glk, with alleles Glka (lower activity) and Glkb (higher activity).
• Strain distribution patterns of Glk closely matched Es-3 alleles, with 31/34 strains showing concordance.
• A map distance of 2.5 cM was estimated between Glk and Es-3.
• Es-3 is located on the distal end of chromosome 11, suggesting Glk is in the same region.

Conclusions:

• Galactokinase activity in mice is controlled by a single gene locus, Glk.
• The Glk locus is located on chromosome 11, linked to the esterase-3 locus.
• This genetic mapping provides insights into the regulation of galactokinase activity and potential metabolic pathways.