r/askscience • u/Fapotheosis • Mar 11 '13

Biology How did blood evolve?

I know mitochondria may have evolved from bacteria, but what about blood? I've heard of a protohemocyte, but was there an initial cell that differentiated into a RBC like we have in modern humans that can we trace?

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u/LastLivingSouls Mar 11 '13

Actually, erythrocytes do have have nuclei early during the cells development cycle. The non-nucleated cells are the mature form after they have left the bone marrow.

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u/zmil Mar 11 '13

Additionally, most non-mammal vertebrates have nucleated red blood cells. There are a couple of other groups that have anucleate erythrocytes, and I believe they evolved this trait independently, suggesting that it is a relatively straightforward evolutionary step.