Bone microstructure and its associated genetic variability in 12 inbred mouse strains: microCT study and in silico genome scan.
MicroCT analysis of 12 inbred strains of mice identified 5 novel chromosomal regions influencing skeletal phenotype. Bone morphology varied in a compartment- and site-specific fashion across strains and genetic influences contributed to the morphometric similarities observed in femoral and vertebral bone within the trabecular bone compartment.


BACKGROUND
Skeletal development is known to be regulated by both heritable and environmental factors, but whether genetic influence on peak bone mass is site- or compartment-specific is unknown. This study examined the genetic variation of cortical and trabecular bone microarchitecture across 12 strains of mice.


METHODS
MicroCT scanning was used to measure trabecular and cortical bone morphometry in the femur and vertebra of 12 strains of 4-month-old inbred male mice. A computational genome mapping technique was used to identify chromosomal intervals associated with skeletal traits.


RESULTS
Skeletal microarchitecture varied in a compartment- and site-specific fashion across strains. Genome mapping identified 13 chromosomal intervals associated with skeletal traits and 5 of these intervals were novel. Trabecular microarchitecture in different bone sites correlated across strains and most of the chromosomal intervals associated with these trabecular traits were shared between skeletal sites. Conversely, no chromosomal intervals were shared between the trabecular and cortical bone compartments in the femur, even though there was a strong correlation for these different bone compartments across strains, suggesting site-specific regulation by environmental or intrinsic factors.


CONCLUSIONS
In summary, these data confirm that there are distinct genetic determinants that define the skeletal phenotype at the time when peak bone mass is being acquired, and that genomic regulation of bone morphology is specific for skeletal compartment.
Sabsovich
Ilya
I
Physical Medicine and Rehabilitation Service, Veterans Affairs Palo Alto Health Care System, Palo Alto, California 94304, USA. isabo@stanford.edu
Clark
J David
JD
Liao
Guochun
G
Peltz
Gary
G
Lindsey
Derek P
DP
Jacobs
Christopher R
CR
Yao
Wei
W
Guo
Tian-Zhi
TZ
Kingery
Wade S
WS
D000818:Animals; D001842:Bone and Bones / Q000166:cytology* / Q000378:metabolism*; D019295:Computational Biology; D005260:Female; D016678:Genome / Q000235:genetics*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D014057:Tomography, X-Ray Computed