Limbs have a proximodistal axis that usually is not apparent early in development, a striking example of epigenesis. The proximodistal axis was the subject of experimental and theoretical study before any molecular genetic understanding emerged. As developmental genetic studies in Drosophila advanced, the descriptive polar coordinate model of the 1970s evolved into an understanding of how preex...

background: human β-like globin genes regulaon during development from embyonic to adult stage results in generaon of different types of hemoglobin with different funcons. as β-thalassemia and sickle cell disease are disorders of β-globin chain, epigenec drugs such as thalidomide and sodium butyrate which can induce γ-globin gene are considered as a novel therapeuc approach. drugs effecve...

In this article, we contrast evolutionary and psychobiological models of individual development to address the idea that individual development occurring in prototypically risky and unsupportive environments can be understood as adaptation. We question traditional evolutionary explanations of individual development, calling on the principle of probabilistic epigenesis to suggest that individual...

Best known for his contributions to the field of embryology [6], Karl Ernst von Baer [5] also pursued a variety of other areas of study including medicine, botany, zoology, and anthropology. Committing his life to scientific research, von Baer?s work led to the advancement of the understanding of mammalian reproduction, development, and organ functioning. His embryological discoveries ultimatel...

The germ line and soma together maintain genetic lineages from generation to generation: the germ line passes genetic information between generations; the soma is the vehicle for germ line transmission, and is shaped by natural selection. The germ line and somatic lineages arise simultaneously in early embryos, but how their development is related depends on how primordial germ cells (PGC) are ...