Question

Please put me out of my misery. How is it possible no one person’s finger prints are the same as another’s? How can one developing embryo possible know what pattern another developing embryo has chosen?

Answer

The movies say that if your fingerprints are found at the scene of the crime, you’re guilty. But does this notion hold up in the real world. Forensic scientist Professor Niamh Nic Daeid, put me through my paces at our very own virtual crime scene where, would you believe it, the murderer has left his fingerprints on the candlestick in the dining room.

• In forensic science, we’re moving away from the notion that fingerprints can be considered as unique and instead talk about the comparison between fingerprints and finger marks.
• Fingerprints are the records that are taken directly from a person’s finger by law enforcement and finger marks are what we take from crime scenes.
• There are a range of characteristic patterns, called friction ridge patterns, which can be used to identify and compare fingerprints. They include: whirls, loops, arches and the location of ridge divisions.
• Ridge patterns also occur on the palms of your hands and on your toes.
• Fingerprints develop in the womb around the 10^th week of pregnancy and are largely complete by the end of the fourth month.
• Factors that influence their development include blood pressure, oxygen levels in the blood, the position adopted by the foetus in the womb, nutrition, hormone levels and the touching of fingers onto the sac and amniotic fluid, which means that even identical twins have different fingerprints!

You can listen to the full interview with the Naked Scientists here.