Genealogy is one of the fastest-growing pastimes in the country, with more people joining the ranks of those searching for their ancestors every day. Denison is offering the community an opportunity to explore this process, and perhaps their own ancestry, with a screening of the “The Human Family Tree,” at 5:30 p.m. on Tuesday, July 19, at a Science Café in the Burton D. Morgan Center Lecture Hall (150 Ridge Road). The film and following discussion are free and open to the public. In addition, attendees are eligible to enter a lottery to win a Genographic Project DNA kit to help them learn more about their unique ancestry. The film’s duration is 90 minutes, and its content is appropriate for upper-elementary school children and older, and families are encouraged to attend. Snacks will be provided during the discussion.

“The Human Family Tree” is a National Geographic documentary that traces the ancestry of seven people from Queens, N.Y., one of the most diverse communities in the country and the world. Narrated by Spencer Wells, a population geneticist and National Geographic Explorer-in-Residence, the film is a result of National Geographic’s Genographic Project, a multi-year research initiative to determine when and where ancient humans moved around the world by mapping the genetic markers in modern-day peoples.

Wells, director of the Genographic Project and holder of a Ph.D. in biology from Harvard, will visit Denison in person at 8 p.m. on Thursday, Oct. 8, as the keynote speaker for the college’s 2011-12 Spectrum Series theme, “Migrations.”

The screening and discussion are sponsored by the Denison chapter of Sigma Xi, a scientific research society that recognizes student excellence in analytical exploration and hosts a series of “science cafés” to encourage conversations about topics of scientific interest.