Mapping Data

Experiment

• Experiment
  TEXT-Congenic
• Chromosome
  1
• Reference
  J:150137 Laissue P, et al., Identification of Quantitative Trait Loci responsible for embryonic lethality in mice assessed by ultrasonography. Int J Dev Biol. 2009;53(4):623-9
• ID
  MGI:5816099

Genes

Gene
Led2

Notes

• Experiment
  The aim of this study was to identify quantitative trait loci (QTL) associated with embryonic lethality and the subsequent embryonic resorption. Fifty three interspecific recombinant congenic strains (IRCS) were used. Originally Mus spretus mouse strain SEG/Pas was crossed with Mus musculus domesticus, C57BL/6J (B6) ultimately creating IRCS mice with 2% of the Mus spretus genome fixed at a homozygous state on a C57BL/6J background (98%).
  
  To identify QTL associated with embryonic death 207 pregnant mice from 39 of the 53 IRC strains and a control group of 22 C57BL/6J mice were examined. Overall a total of 1581 ultrasonic examinations from pregnant and non pregnant mice were performed. Phenotypically the dead embryos were classified into two categories: early embryonic death (EED) and late embryonic death (LED). Embryos presenting the LED phenotype displayed a heartbeat arrest and an absence of umbilical cord flow.
  
  A total of respectively 1603 and 195 embryos from IRCS and B6 (control group) were analyzed by ultrasound biomicroscopy searching to establish major anatomical anomalies of the vagina, uterus, and the ovaries. Variables observed were the number of implanted embryos, the number of dead embryos, the position of implantation, the sex ratio of surviving pups at 3 days. Statistically, p<0.05 was considered significant.
  
  Among the 39 strains studied, 4 strains were identified (BcG66H/Pas, BcG103C/Pas, BcG135B/Pas and BcG135E/Pas) displaying a highly significant increase in embryonic lethality ratio (ELR) - defined as the proportion of dead embryos at any stage of development relative to the totality of the implanted embryos compared with the control group.
  
  The BcG66H/Pas strain encompassed three spretus genomic fragments located on Chromosomes MMU1, MMU13 and MMU18. Three substrains derived from BcG66H/Pas were created and phenotyped, each containing a unique spretus fragment: BcG66H-MMU1, BcG66H-MMU13 and BcG66H-MMU18. An increase in ELR was observed in both BcG66H-MMU1 (24.6%, p=0.013) and BcG66H-MMU13 (14.7%, p=0.01).
  
  Ultimately, 3 QTL associated with embryonic lethality were unambiguously mapped on single chromosome segments from strains containing unique spretus fragments:
  
  QTL, Led1 (late embryonic death 1) was mapped on Chromosome 13 in substrain B6.SEG-(rs120693734-D13Mit47). An approximate 3.4 Mb interval containing 31 genes, Table 3.
  
  QTL, Led2 (late embryonic death 2) was mapped on Chromosome 1 in substrain B6.SEG-(D1Mit50-rs120683504) corresponding to a large 18.3 Mb area not shared with any other IRCS strain. The interval contained 215 genes ( 143 described and 72 predicted).
  
  An additional QTL, Led3 (late embryonic death 3) was mapped on Chromosome 19 in substrain B6.SEG-(D19Mit49-D19Mit137) which carried a unique spretus fragment.