Each year thousands of teary-eyed pet-lovers turn to science to immortalise their departed companions, and a Hong Kong-based biotechnology company is helping them to do just that. LAByrinth launched a service in 1999 which preserves the unique genetic code or DNA of dearly departed pets in the form of a necklace. Happily for LAByrinth (but sadly for pet owners) business is booming, with about 20 per cent growth in sales each year. Assistant sales administration manager Michael Hui Hung-kit said the company took more than 200 orders for pet DNA necklaces a month. The laboratory has already produced more than 2,000 this year. Mr Hui said the growth in business had been 'outstanding' and included sales to Japan, Britain, Italy, Australia and Singapore. But he said most business came from Hong Kong residents seeking a special tribute to their dead pets. 'When animals die, many owners want to have something to keep for their memories. Many Hong Kong people are very attached to their pets,' Mr Hui said. 'The DNA necklace is a unique unified material from their pet and is starting to replace photographs and other types of memorials. 'It is a very simple idea that has developed into a successful business.' Most of the company's business is from cat and dog owners, but the company has also made necklaces with DNA from rabbits, rodents, birds and fish. The process involves swabbing the inside of the mouth to collect buccal cells. This can be done using a collection kit provided by the biotechnology company on either a deceased or living animal. A large number of DNA molecules are extracted and preserved in a crystalline form, with the process taking about a week. The DNA is then placed in a vial with a non-toxic mixture of glycerol and water so that it can be seen by the naked eye. Necklaces come in three colours: violet, aqua or ice (clear) in an array of different styles, and each necklace costs a few hundred dollars.