Experiment
Linkage analysis was performed on 1040 (LG/J x SM/J)F2 animals to identify genetic loci associated with skeletal traits. The F2 population consists of two sets of intercrosses where intercross I (n=533) was phenotyped at 10-weeks of age and intercross II(n=507) was phenotyped between 72- and 237-days of age. Parental strain LG/J displays increased body weight compared to SM/J. Seventy skeletal traits were measured. Intercross I was genotyped for 76 microsatellite markers on 19 autosomes (excluding X chromosome). Intercross II was genotyped at 95 microsatellite markers and 369 SNP markers, including 16 SNPs on chromosome X. One hundred five pleiotropic loci were identified representing 798 single trait QTLs. The average number of traits associated per QTLwas 7.6. In general, LG/J-derived alleles confer increased skeletal trait measurements.
The QTL interval for Plskt40 (pleiotropic skeletal traits 40) spans 1 cM to 11 cM with peak linkage occurring at 5 cM. Skeletal traits associated with Plskt40 include zygomatic length, cranial vault length and width, hindlimb ischium length, ischaic-pubic ramus length, hindlimb obturator foramen length, face height in females, pubic symphysis length in males and basicranial length.
Plskt41 (pleiotropic skeletal traits 41) maps to 20 cM and is associated with four skeletal traits, including eighth thoracic length in females and third thoracic centrum height and length. The confidence interval spans 10 cM to 28 cM.
Plskt42 (pleiotropic skeletal traits 42) maps to 32.6cM and is associated with nine skeletal traits. The Plskt42 confidence interval spans 27 cM to 51 cM. This locus is associated with skeletal traits including hindlimb innominate length and ilium length, forelimb infraspinous length, humerus length, tibialength, femur length, sacroilium joint length, third metatarsal length and tail length.
The QTL confidence interval of Plskt43 (pleiotropic skeletal traits 43) spans 43 cM to 49 cM. Plskt43 is associated with sixteen skeletal traits with peak linkage at 45.7 cM. Skeletal traits linked to Plskt43 include sacral length, ulna length, forelimb superior spinous length, necropsy weight, body weight at 10 weeks of age, zygomatic width and length, hindlimb calcaneus length, scapula spine length, face length and width, third thoracic length, pubis length in females, mandible square root of masseteric area and third caudal length.
Plskt44 (pleiotropic skeletal traits 44) displays peak linkage to two skeletal traits, sacral width and mandible square root of angular process area in females, at 90 cM. The QTL confidence interval spans 52 cM to 91 cM.
Analysis Tools