@article{ref1,
title="Probing an evolutionary riddle",
journal="Science",
year="2019",
author="Culotta, Elizabeth",
volume="365",
number="6455",
pages="748-749",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0036-8075",
doi="10.1126/science.365.6455.748",
url="http://dx.doi.org/10.1126/science.365.6455.748"
}