Human limbs may have gotten their start as gill arches

Discussion in 'Biology & Genetics' started by Plazma Inferno!, Apr 20, 2016.

  1. Plazma Inferno! Ding Ding Ding Ding Administrator

    New genetic evidence suggests the evolutionary origins of human limbs lie in the gill arches of sharks, skates and rays.
    Gill arches are the collection of looped bones that support gills and serve as the sprouting point for gill arch appendages, or branchial rays. Biologists have suggested gill arches laid the evolutionary foundation for paired fins in early fish, which later paved the way for paired limbs in mammals.
    Now there's the genetic evidence to back up this theory.
    In looking at the embryonic development of limbs, fins and gill arches, scientists identified a gene known as "Sonic the hedgehog" that plays a similar role governing the formation of all three features. The gene produces a signaling protein that plays a key role in determining the axis of development and later controls limb skeleton growth.

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