Genome distance between growth-regulating genes and telomeres is correlated with morpho-physiological traits in mammals

Abstract

The problem of the growth regulation in mammals is one of the long-standing mysteries in biology. The growth rate is high in early postnatal life, but then decreases and eventually ceases in multiple tissues, determining adult body size, different for different mammals. Age-related changes in growth rate in mammals were shown to be associated with declining in expression of the small set of growth-promoting genes. On the other hand, somatotropic axis genes are known to be involved in the systemic growth regulation. We investigated the relationship between some morpho-physiological traits of mammals and chromosomal locations of these genes relative to telomeres across mammals. We found that gene-telomere distance is correlated with age of maturity of mammals for only two somatotropic axis genes Ghrh and Sst. We suggested that recently discovered telomere position effect over long distances (TPE-OLD) may be involved. Strikingly, we found that gene-telomere distance for two TPE-OLD regulated genes C1s and Notch1 is also correlated exactly with age of maturity. We supposed that influence of TPE-OLD may decay with increasing gene-telomere distance. We hypothesize that TPE-OLD may also be involved in regulation of genes Ghrh and Sst, variation of gene-telomere distance across mammals being the cause of evolutionary difference in morpho-physiological traits of mammals.