The article suggests the cause is evolution/genes, not environmental conditions such as infection: "The observed increase therefore in the prevalence of persi

The article suggests the cause is evolution/genes, not environmental conditions such as infection: "The observed increase therefore in the prevalence of persistent median arteries in adult forearms of people in many countries may be a trend associated with the evolutionary process." If I'm reading the paper correctly, they're not suggesting that this is because the artery provides some survival or reproductive advantage. They're just saying the trend is likely to continue.