A former Lexington resident is one of 30 national finalists for the prestigious White House Fellows Program.
If chosen, Sarah Johnson, 29, would spend a year working as a special assistant to one of the government's highest-ranking officials.
Johnson is in the first year of a three-year Junior Fellowship with the Harvard Society of Fellows, where she is helping to develop experiments that will be used to look for "genetic signatures of life" on the 2012 Mars rover expedition, said her father, John Johnson.
There are two years remaining on Johnson's Harvard fellowship. She will take a yearlong leave of absence from it if she is selected as a White House Fellow, said her mother, Kate Johnson, of Lexington.
"She's a really spirited young woman with a lot of imagination," Kate Johnson said.
Johnson graduated from Henry Clay High School in 1997 and earned a bachelor's degree in theoretical mathematics and environmental studies from Washington University in St. Louis.
She earned a master's degree in biology from Oxford University while studying there as a Rhodes Scholar.
She completed a doctorate in planetary science from the Massachusetts Institute of Technology last year.
Next month, Johnson and other finalists will spend 21/2 days being interviewed and observed by the President's Commission on White House Fellowships, which will then recommend a group of finalists for presidential appointment to the fellowship. The program's Web site says 11 to 19 finalists typically are appointed.
Johnson is looking forward to meeting first lady Michelle Obama as part of that process, her mother said.
Kate Johnson said her daughter described the interviews that got her this far as stressful but exciting.