The Bute Museum is investigating a possible link between the island and the largest loss of life in Australian naval history.
The possible Bute connection lies with 94-year-old Australian resident Margaret Leyland, who was born in Glasgow in 1921 but whose family hailed from Rothesay.
DNA testing has shown that Mrs Leyland is related to the only man whose body was ever found after the cruiser HMAS Sydney sank under German attack in November 1941, with the loss of all 645 crew.
That one body was washed up and then buried on Christmas Island in the Pacific Ocean in 1942, though it was recovered in 2006 and later re-interred in Australia with full military honours.
Although DNA samples were taken before it was reburied, the body still hasn’t been conclusively identified.
Bute Museum volunteer Isabel Sharp, who is leading the hunt from the Bute perspective, told us: “Mitochondrial DNA testing shows Mrs Leyland is a close relative of the crewman, but not his sister as first thought.
“The DNA experts think a previous generation emigrated from the west of Scotland, and hope to find a female descendant of another line.”
Mrs Leyland, whose maiden name was McCallum, emigrated to Australia in 1939 with her brother - though not with their parents.
Her mother, Janet Cameron, was born in Rothesay in 1883 and later married a Neil McCallum. Janet’s mother, meanwhile, was an Annie Scott, who was also born in Rothesay, in 1861.
The female family line holds the key to identifying the sailor’s body, so if you know of a connection to Margaret McCallum, Janet Cameron or Annie Scott, and think you might be able to help in the search, you can contact email@example.com or call the museum on (01700) 505067.