To test whether enhancer activity — and therefore gene regulation — is similar in fish gills and human outer ears, Crump and his colleagues inserted human outer ear enhancers into zebrafish ...

(Adult human brains typically weigh about three pounds.) No known living vertebrate has so miniscule a brain in relation to ... The coelacanth has gills similar to those of fish living at the ...

The authors reasoned that many similarities between the appearance of cartilage under the microscope for zebrafish gills and human ears cannot be just a coincidence. Knowing that both the gills ...