Natural history book
Even though the unique bird specimen illustrated in this book had been described as a new species of starling (Necrospar leguati), no other specimens of starling from Madagascar were known. In 2003 scientists analyzed the DNA in tiny samples of the skin from the specimen to find out more about it. This showed that this bird is really a rare albino form of a species of mockingbird, the Gray Trembler (Cinclocerthia gutturalis) from the West Indies. The locality was an error on the original label.
How can analysis of a specimen's DNA (Deoxyribonucleic Acid) tell us more?
'The Natural History of Sokotra and Abd-el-Kuri' by HO Forbes, 1903
DNA is a chemical found in the nucleus of cells of virtually all living organisms and carries hereditary information. Every individual’s DNA is unique - with the exception of identical twins. As DNA carries information from generation to generation it can be used to understand relationships between individuals, species and broader classifications. DNA can be analysed chemically into pattern of bands on photographic film and the pattern of bands is used to decipher relationships between organisms.
The long chain molecule of DNA has a unique sequence of sub-units along its length. The chain can be split into a series of sections, with the break between the same sub-units for every molecule. Because the sequence and number of sub-units is different for every organism, the sections will have different lengths, depending from which organism they originate.
Long and short lengths of DNA can be separated by a small electric current passing through a gel onto which the mixture of DNA sections has been placed. The resulting series of DNA bands can be made visible and patterns of bands from different organisms compared to see how similar or different they are.