Bone provides structure to the vertebrate body that allows for movement and mechanical stimuli that enable and the proper development of neighboring organs. Bone morphology and density is also highly heritable. In humans, heritability of bone mineral density has been estimated to be 50–80%. However, genome wide association studies have so far explained only 25% of the variation in bone mineral density, suggesting that a substantial portion of the heritability of bone mineral density may be due to environmental factors. Here we explore the idea that the gut microbiome is a heritable environmental factor that contributes to bone morphology and density. The vertebrae skeleton has evolved over the past ~500 million years in the presence of commensal microbial communities. The composition of the commensal microbial communities has co-evolved with the hosts resulting in species-specific microbial populations associated with vertebrate phylogeny. Furthermore, a substantial portion of the gut microbiome is acquired through familial transfer. Recent studies suggest that the gut microbiome also influences postnatal development. Here we review studies from the past decade in mice that have shown that the presence of the gut microbiome can influence postnatal bone growth regulating bone morphology and density. These studies indicate that the presence of the gut microbiome may increase longitudinal bone growth and appositional bone growth, resulting differences cortical bone morphology in long bones. More surprising, however are recent studies showing that transfer of the gut microbiota among inbred mouse strains with distinct bone phenotypes can alter postnatal development and adult bone morphology. Together these studies support the concept that the gut microbiome is a contributor to skeletal phenotype.

骨骼为脊椎动物身体提供结构，允许运动和机械刺激，从而使邻近器官能够正常发育。骨骼形态和密度也具有高度遗传性。在人类中，骨矿物质密度的遗传性估计为 50-80%。然而，迄今为止，全基因组关联研究仅解释了 25% 的骨矿物质密度变异，这表明骨矿物​​质密度的遗传性中有很大一部分可能是由于环境因素造成的。在这里，我们探讨了肠道微生物组是一种可遗传的环境因素，有助于骨骼形态和密度的想法。在共生微生物群落存在的情况下，椎骨骨骼在过去约 5 亿年中已经进化。共生微生物群落的组成与宿主共同进化，导致与脊椎动物系统发育相关的物种特异性微生物种群。此外，很大一部分肠道微生物组是通过家族转移获得的。最近的研究表明，肠道微生物组也会影响出生后发育。在这里，我们回顾了过去十年对小鼠的研究，这些研究表明肠道微生物组的存在可以影响出生后骨骼生长调节骨骼形态和密度。这些研究表明，肠道微生物组的存在可能会增加纵向骨生长和并置骨生长，从而导致长骨皮质骨形态的差异。更令人惊讶的是，然而，最近的研究表明，在具有不同骨骼表型的近交系小鼠品系中肠道微生物群的转移可以改变出生后发育和成年骨骼形态。这些研究共同支持了肠道微生物组是骨骼表型的贡献者这一概念。