Thyct2^DBA/2J
QTL Variant Detail

Summary

• QTL variant: Thyct2^DBA/2J
• Name: thymocyte count 2; DBA/2J
• MGI ID: MGI:3051307
• QTL: Thyct2 Location: unknown Genetic Position: Chr3, cM position of peak correlated region/allele: 66.69 cM
• QTL Note: genome coordinates based on the marker associated with the peak LOD score

Variant origin

• Strain of Specimen: DBA/2J

Variant description

• Allele Type: QTL
• Mutation: Undefined
• This allele confers decreased thymus size compared to C57BL/6J. (J:85261)

Notes

Animals with the smallest and largest thymuses are homozygous at both Thyct1 and Thyct2 for DBA/2J-derived alleles or C57BL/6J-derived alleles, respectively.

Mapping and Phenotype information for this QTL, its variants and associated markers

J:85261

Linkage analysis was performed on 18 BXD (B=C57BL/6J; D=DBA/2J) recombinant inbred (RI) strains to identify QTLs associated with thymic size and rate of thymic involution (age-related shrinkage of the thymus). Parental strain C57BL/6J exhibits significantly higher initial thymocyte counts compared to DBA/2J, and, at 15 months of age, display lesser thymic involution than DBA/2J. Approximately 620 informative markers were used in the genome scan.

Thymic involution QTLs Arti1 (age related thymic involution 1) and Arti2 mapped to 62 cM mouse Chromosome 9 near D9Mit20 (LRS=8) and to 32 cM on mouse Chromosome 10 near D10Mit61 (LRS=7.6), respectively. C57BL/6J-derived alleles confer a slower rate of thymic involution at these loci. There is no evidence of epistasis between Arti1 and Arti2. Animals homozygous for C57BL/6J-derived alleles at both Arti1 and Arti2 have the slowest rates of thymic involution whereas animals homozygous for DBA/2J-derived alleles at both loci have the highest rates of thymic involution. Arti1 maps near a QTL previously identified by Havelkova 1999 named Tria5 (61 cM) associated with differential T cell response to anti-CD3. Arti2 maps near previously identified QTLs associated with immune regulation (Uvbi1, 29 cM), development of autoimmune diseases (Bbaa18, 31.5 cM and Eae17, 36 cM), and lifespan (Lifespan2, 35 cM).

Loci associated with initial thymocyte count Thyct1 (thymocyte count 1) and Thyct2 mapped to 26.5 cM on mouse Chromosome X near DXMit324 (LRS=9.7) and to 70.3 cM on mouse Chromosome 3 near D3Mit127 (LRS=8.7), respectively. (**Note- DXMit324 is not found in MGI. A marker at the same cM position, DXMit110, is indexed by the MGI curator.) C57BL/6J-derived alleles confer increased thymus size at 60 days of age for both loci. Animals with the smallest and largest thymuses are homozygous at both Thyct1 and Thyct2 for DBA/2J-derived alleles or C57BL/6J-derived alleles, respectively. Thyct1 maps near previously identified body size (Bdln1, 17 cM and Bw19, 26.4 cM) and organ weight QTLs (Bw12, 48 cM). Thyct2 maps near a previously identified body weight QTL (Wt10q2, 61 cM).

References

• Original: J:85261 Hsu HC, et al., Age-related thymic involution in C57BL/6J x DBA/2J recombinant-inbred mice maps to mouse chromosomes 9 and 10. Genes Immun. 2003 Sep;4(6):402-10
• All: 1 reference(s)