Old fish bones

In 1996 a shipwreck was discovered during a survey of the Dor lagoon on the Israeli Mediterranean coast, south of  Haifa. Based on some metal objects and Carbon14 tests of some organic materials, the so called Tantura F shipwreck was dated to the 7-8th centuries AD which is known to be the region’s Early Islamic period.

Among the findings were eight amphorae made of Nile Delta silt with resinous linings. The 6-7-liter amphorae contained bones  from all parts of the fish skeleton, indicating that the amphorae once contained whole fish. Preliminary morphological analysis of the bones at the University of Haifa assigned the fish to the genus Tilapia but a group of researchers wanted to confirm the species identities and used short DNA Barcodes (mini-barcodes) to find out which load the ship had carried 1400 years ago.

Given the age of the samples they could only retrieve a 140bp fragment which didn't allow a full species designation but the fact that on this length there was only one bp difference to the two Tilapia species Oreochromis aureus and Sarotherodon galilaeus (transition from G to A) certainly confirms the intitial identification. The authors speculate that the ancient fish belonged to an extinct species or sub-species closely related to the two contemporary species. I find that a bit of a stretch given the short length of the sequences. One nucleotide difference on a length of 140bp. That makes perhaps 5 on the entire DNA Barcode region assuming equal distribution of mutations (unlikely, but for this little exercise it will do). That is probably half a percent divergence. Among fishes that rarely qualifies for different species.

That should not divert from the results as such. I find it pretty cool that DNA Barcoding can help with archeology. Let's not forget that the amphorae contained all parts of the fish skeleton which makes identification by morphology possible. Imagine you only have one little fragment.