Professor Conneally received his B.S. from the University College in Dublin, Ireland and his M.S. and Ph.D. from the University of Wisconsin. In the past two decades he was instrumental in mapping approximately 20 human genes. After a decade of searching for the Huntington disease gene, his work resulted in the identification of 20% of the human genome. When a campaign led by Woody Guthrie's widow convinced the National Institutes of Health to study HD in depth, Dr. Conneally entered and won a nationwide competition for a contract to establish a roster of affected families.
Conneally began collaboration with Dr. James Gusella of Harvard in a search for the Huntington disease gene using recombinant DNA markers. This search began in 1980 and in 1983 the gene was located on chromosome 4. The 1984 International Congress of Human Genetics added this discovery to its list of the 40 most important advances in human genetics.
This same team also searched for a gene causing familial Alzheimer disease. In 1987, an announcement was made in Science that a gene was found on chromosome 21. Later in 1987, in collaboration with investigators at Duke University, Professor Conneally identified a second gene for familial Alzheimer disease. As a result of this work, he was chosen to establish and direct a national roster for the study of familial Alzheimer disease.
In 1988 Conneally was elected to the rank of Distinguished Professor. In 1989, he was awarded an honorary Doctor of Science honoris causa degree by Trinity College, University of Dublin, Ireland, and in 1991 was selected as the Irwin Research Awardee, IUPUI's highest recognition of faculty research accomplishments. In 2001, he received the International Society of Psychiatric Genetics Lifetime Achievement Award and was a president of the American Society of Human Genetics. He authored or co-authored 500 abstracts and publications.