RT Journal Article SR Electronic T1 Changing genes; losing lactase JF Gut JO Gut FD BMJ Publishing Group Ltd and British Society of Gastroenterology SP 617 OP 619 DO 10.1136/gut.52.5.617 VO 52 IS 5 A1 Grand, R J A1 Montgomery, R K A1 Chitkara, D K A1 Hirschhorn, J N YR 2003 UL http://gut.bmj.com/content/52/5/617.1.abstract AB