With further testing, the researchers isolated the likely source of this 18-nucleotide fragment of RNA.
It seems to result as a byproduct from a larger RNA that is cut by enzymes during storage, and it happens in a very precise, predictable way.
"This increase in mi R-720 is significant enough and consistent enough that it could be used as a biomarker for detecting stored red blood cells," Chi said.
He said further research is focused on understanding why the enzyme that produces mi R-720 is active in stored cells and what it might be doing as it breaks a larger RNA apart. "New finding could unmask blood doping in athletes: RNA changes mark old blood cells among new ones, foiling self-transfusions." Science Daily. Neurologists have provided, for the first time, evidence that blood deposits in the brain may not require a blood vessel tear.
The racing results of the country’s middle- and long-distance runners were tracked to produce an Athlete’s Performance Passport (APP), an analog of the Athlete’s Biological Passport (ABP) that had recently been introduced to look for suspicious aberrations in blood test results.
No two races are the same, but when conditions are similar, elite endurance runners tend to produce performances that vary from race to race by 1 to 1.4 percent, according to one study.
The anti-doping agency had been tracking the athlete for 239 days leading up to the marathon, regularly updating their predictions based on his most recent race results.
When he ran a then-best time of earlier in the year, it was just 0.22 percent faster than the prediction of based on a previous half marathon and a 12K result. At this point, you’d be forgiven for being a bit skeptical.