Mapping Data

Experiment

• Experiment
  TEXT-Congenic
• Chromosome
  4
• Reference
  J:183482 Gotoh H, et al., QTL on mouse chromosomes 1 and 4 causing sperm-head morphological abnormality and male subfertility. Mamm Genome. 2012 Aug;23(7-8):399-403
• ID
  MGI:5816277

Genes

Gene
Shm2

Notes

• Experiment
  The B10.M-H2^f H2-T18 ^a?/SnJSgn (B10.M) mouse strain represents a model for sub fertility as it produces a significantly low number of offspring. The only known male reproductive phenotype of the strain is its high frequency of sperm-head morphological abnormalities.
  
  In this study the loci causing the high frequency of sperm-head morphological abnormalities were mapped using F2 progeny created from crossing B10.M and C3H/HeNCrlCrlj (C3H) mice. The B10.M mice originally purchased from the Jackson Laboratory were maintained in house for more than ten generations of inbreeding; the subline was designated as B10.M/Sgn.
  
  159 microsatellite DNA markers were used for the genome wide scan between the two strains. Two to three month old male mice were used for the collection of sperm samples for the sperm-head morphology tests. QTL analysis was performed using R/qtl software. The statistically significant LOD threshold (p=0.05) for the phenotype, as determined by permutation test (n=1000) was 3.47.
  
  QTL analysis was performed on 178 (C3H x B10.M) F2 mice. In the whole genome analysis two significant peaks were identified on Chromosome 1 and on Chromosome 4. Genetic mapping analysis performed according to the genotypes of the F2 progeny (N=854) further refined the QTL intervals.
  
  QTL Shm1 (sperm head morphology 1) mapped to Chromosome 1 with a peak at 23.7 cM and a LOD score of 30.585, between markers Ercc5 (23.55 cM) and D1Mit528 (25.95 cM).
  
  QTL Shm2 (sperm head morphology 2) mapped the Chromosome 4 with a peak at 70.4 cM and a LOD score of 4.532, between markers D4Mit148 (69.48 cM) and D4Mit170 (70.47 cM).
  
  The frequency of sperm head abnormalities was plotted for each Shm1 and Shm2 genotype. A significant difference was observed between B10.M Shm1 homozygous mice and those with other genotypes, p<0.05. A significant difference was also observed within the B10.M Shm1 homozygous and between B10.M Shm2 homozygotes and mice with other genotypes, p<0.05. The conclusion was that the Shm1 locus was the major locus for sperm head abnormalities, while the Shm2 locus on Chr 4 modified the degree of abnormalities positively in a recessive manner only when the genotype of the Shm1 locus was homozygous for the B10.M allele.