Here’s a little-known fact about that highly expensive condiment you put on your Chipotle burrito: avocado trees are constantly changing their sex. Throughout the day, an avocado tree alternates between male and female flowers. Why it does this has been a mystery for about a century.

Now, a new study from researchers at the University of California, Davis, may have finally figured it out.

According to UC Davis and the study published in Proceedings of the National Academy of Sciences, scientists identified a gene called SDMYB that controls its constantly shifting reproductive schedule.

Avocado Trees Switch Sex Throughout the Day. Scientists Finally Know How.

Avocado trees are technically hermaphrodites, but the flowers don’t play the role of both sexes at the same time. A-type varieties, like the deliciously creamy Hass avocados most likely to be served up at your local Mexican restaurant, kickstart the day as females in the morning and become males in the afternoon.

And then there’s B-types, which have the opposite schedule. This helps trees exchange pollen instead of fertilizing themselves, which, as you can imagine, could lead to issues, leaving them weak and disease-ridden and, well, if you know anything about inbreeding, then you get it.

SDMYB controls this behavior, telling the tree when its flowers need to be male or female. This will ultimately prove extremely valuable for avocado farmers, since before this discovery avocado breeders had to plant hundreds of young trees and then wait several years for them to reach maturity to figure out whether it’s an A-type or B-type. Now, they can potentially look at the tree DNA while it’s still young and determine which type it’ll be.

Putting some B-type trees near some A-type trees will help them pollinate each other instead of pollinating like with like, which will help farmers meet the American consumer’s insatiable desire for avocados, since avocado consumption has quadrupled since 2000.

This could lead to more efficient breeding and help produce more avocado varieties better suited to a changing climate and a populace that is ever ravenous for guac.

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