2000 Year-old ancient equids: an ancient-DNA lesson from pompeii remains.

This research paper investigates ancient DNA derived from 2000 year-old horse bones. Using specific sequences, researchers amplified mitochondrial and nuclear DNA fragments from these bones with aims of comparing them with modern horses and assessing their genetic relationship.

Extraction of Ancient DNA

• The study focuses on ancient DNA (aDNA) extracted from 2000 year-old equine bones found in Pompeii. The extraction of aDNA allows scientists to trace the genetic history of organisms and draw conclusions about their evolution or relationship with current species.

Amplification of DNA Fragments

• After the extraction, the aDNA was subjected to amplification to create multiple copies of certain DNA fragments. This amplification was focused on both mitochondrial and nuclear DNA.
• A specific equine satellite-type sequence was targeted for this process. Equine satellite-type sequences represent 3.7% to 11% of the total horse genome. This target was chosen to address the presence of aDNA in the bones.

Polymerase Chain Reaction Strategy

• Next, a polymerase chain reaction (PCR) strategy was designed to investigate this specific target. The PCR technique is commonly used in genetics research to create numerous copies of a particular DNA segment.
• This technique also enabled the researchers to calculate the molecular weight of the amplifiable DNA fragments.

Sequencing and Comparing DNA sequences

• A 370 base pair (bp) DNA fragment of the mitochondrial control region was sequenced. This allowed for the comparison of ancient DNA sequences with modern horses to understand their genetic relationship. This comparison suggested possible genetic evolution or continuity from the ancient equids to the current horse population.

Investigation of the 16S rRNA mitochondrial gene

• In addition to the above research, the 16S rRNA mitochondrial gene was examined to study the post-mortem base modification feature. This post-mortem modification gives insights into the changes in the gene after the organism’s death. It sheds light on the genetic stability or variations post-mortem.
• This gene was also examined to test the taxonomic status of the Pompeian equids using a Mae III restriction site polymorphism. This helps in checking the species or subspecies classification of the ancient horses.