====== Hand and digits evolution ======

>__How the hand and digits originated from fish fins during the Devonian fin-to-limb transition remains unsolved.__ Controversy in this conundrum stems from the scarcity of ontogenetic data from extant lobe-finned fishes."
>\\ Source : [[https://www.science.org/doi/full/10.1126/sciadv.abc3510|Science Advances Vol. 6, No. 34]]{{:oa_padlock_grn.png?16}}

Various transformational theories for the  'fin-to-limb transition' were first proposed in the 19th century, and recently have been integrated with ideas from developmental biology and gene regulation.

However :

>Today, competing mutually incompatible hypotheses propose that digits could result from adoption of a dermoskeletal genetic network by the distal endoskeleton following the evolutionary loss of fin rays, or alternatively, that they arose through the emergence of new forms of the //hox// gene regulation producing limb-specific gene expression domains."\\ \\ [ source as above ]