Genetic Diversity of the Date Palm

As a traditional staple of the Arab diet, dates have long had a central place in both the agricultural economics and the culinary repertoire of the UAE. Now Khaled Hazzouri, a postdoctoral associate at the Center for Genomics and Systems Biology at NYU Abu Dhabi, is working to discover the genetic origins of this iconic fruit.

Working on the 100 Dates! Project, led by NYU's Dorothy Schiff Professor of Genomics (and Dean of Science) Michael Purugganan, Hazzouri collects samples of different date varieties and performs whole-genome deep sequencing, a process that provides detailed information about an organism's genetic makeup.

Other researchers have investigated the domestication of the date palm in particular regions, but 100 Dates! takes a broad view, working with samples obtained from North Africa, Pakistan, and points in between.

"People claim that the center of diversity for the date palm is Iraq. Others say Iran, Pakistan, or Egypt," Hazzouri said. "There is some archaeological data to support these arguments, but in order to know for sure, we really need to do a full genome study with many samples." Hazzouri thinks that today's date palm, like other crops from rice to apples, may have developed from multiple domestication events.

The team hopes to expand its sample from the original 100 varieties to 500 or even 1,000. "With the samples we already have, we've done deep sequencing and we have information about a lot of the most important mutations that have happened in dates over the course of their domestication," Hazzouri said.

A wild ancestor of the date palm was likely cultivated by humans over several thousand years, developing in the process into the many varieties seen around the region today.

"Farmers of the past may have seen these wild plants and recognized in them particular traits that they thought were valuable, and they would select the trees that had those traits for further cultivation," Hazzouri explained.

The team hopes to make a "roadmap" of at least 400 date varieties that correlates the characteristics (color and sweetness, for example) of the different varieties with the genetic markers that code for those particular traits.

This work will help researchers know how genes affect different traits of the tree, such as fruit sweetness and yield and the ability of the trees to tolerate high salinity.

It may even help farmers in the region improve their yields by cultivating varieties that are well suited to the environment.

This article originally appeared in NYUAD's 2013-14 Research Report (13MB PDF).