By Danielle Ozbat Christmas Mothers from past and present gathered at the historic Magnolia Grange museum house last Tuesday to announce Deborah Koller as this year’s Chesterfield-Colonial Heights Christmas Mother. Koller – who holds a bachelor’s degree in biology, a master’s degree in microbiology and a doctorate in molecular genetics – has been with the Christmas Mother committee for four years and is honored to be chosen. “It’s an honor, a little humbling [and] I just hope I can serve the organization well,” Koller said. “We sort of  work as the interface … between the organization and the public, letting…