Mouse sperm motility affected by factors in the T/t complex

Area of Science:

• Reproductive biology
• Genetics
• Sperm motility analysis

Background:

• The transmission ratio distortion (TRD) of certain genetic elements, like tw32, can be influenced by male reproductive factors.
• Understanding sperm function is crucial for investigating mechanisms of TRD.

Purpose of the Study:

• To compare the motility characteristics of epididymal sperm from tw32/+ and T/+ male mice with their respective wild-type congenic strains.
• To investigate potential correlations between altered sperm motility and the high male transmission of the tw32 genetic element.

Main Methods:

• Comparative analysis of epididymal sperm motility and velocity in various mouse genotypes (tw32/+ and T/+ vs. wild-type).
• In vitro assessment of sperm motility, adhesivity to glass, and swimming trajectory patterns over 7.5 hours.
• Measurement of apparent mean sperm velocities using microscopy.

Main Results:

• Sperm from B6-tw32/+ males showed significantly decreased vigorous motility and increased glass adhesivity compared to B6-+/+ controls.
• Apparent mean velocities of epididymal sperm from tw32/+ males were significantly lower across all tested strains compared to wild-type congenic counterparts.
• Erratic and convoluted swimming trajectories were prevalent in sperm from tw32/+ males, suggesting altered motility patterns.

Conclusions:

• Motility defects, including reduced velocity and abnormal trajectories, are associated with the tw32/+ genotype in mice.
• These observed sperm motility differences may contribute to the high male-biased transmission of the tw32 genetic element.