Mark S. Ptashne is the Renaissance man of Harvard's molecular and cellular biology department.

In addition to being one of the world's foremost molecular biologists, he is also an accomplished violinist, businessperson and art collector.

Ptashne, the Smith professor of molecular biology, says he doesn't know whether his musical talents help him in his scientific research, but he notes that few scientists have such a "peculiar" lifestyle.

"Music goes through my head all the time and that doesn't make me a musician, it's just a fact--it could be that it influences how I write a sentence or think about scientific problems," Ptashne says.

Ptashne demonstrated his skill with the violin at a party he hosted two weeks ago in his Cambridge home to honor Jannic Nusslein-Vol-hard and Eric Wieschaus. The two German researchers will receive this year's Nobel Prize in medicine in December for their research on the development of fruit-fly embryos.

Melvin Chen, a chemistry tutor in Currier House who studied music at the Juilliard School in New York, has practiced the violin several times with Ptashne and accompanied Ptashne in a performance at the party.

"We played a Telemann sonata and some Bartok and the audience was pretty enthusiastic; they liked it," Chen says.

Ptashne says he began playing the violin at age 15 and has improved tremendously in the past decade. Much of the impetus for that improvement has been Ptashne's continual acquisition of better-sounding violins.

"At every stage of my career, whatever money I had plus whatever I could borrow involved a violin," Ptashne says. "It's like houses, you trade up and trade up."

Ptashne says that for much of his life, he has sought a violin capable of producing a peculiarly high-quality sound that has obsessed him for many years.

"I've always had a certain sound in mind and was haunted by that," Ptashne says. "The motivation for what I have done, particularly starting a company, was to afford a better and better violin."

Ptashne says he even tried to convince then-president Derek C. Bok to have the University loan him money to purchase an early Stradivari violin, widely regarded as the best instruments in the world.

Bok did not approve the loan, but undaunted, Ptashne says he sold shares in the violin to friends, which put him "way into debt."

Every July, Ptashne plays at the Yellow Barn Festival, a music festival in Boston sponsored by the New England Music Conservatory. Ptashne says he studies at the Conservatory and tries to practice at least two hours a day.

At the party, Ptashne and Chen played two famous Guarnieri violins which make up part of Ptashne's instrument collection. Chen played the D'Egville, the violin that musician Yehudi Menuhin used to build his career.

"About 10 years ago I got a call from a dealer who said he had the D'Egville," Ptashne says. "I tried the violin and immediately loved it but had very little time to decide."