Contrary to common belief, smile dimples are not caused by a single dominant gene but rather by an anatomical variation in the zygomaticus major muscle. This muscle, which typically runs unbroken from the cheekbone to the lip, splits in some individuals, causing one slip to attach to the skin and pull it inward when smiling. While this trait appears in about one in five people, its inheritance pattern is complex, influenced by multiple genes and developmental chance rather than a simple Mendelian model. AI
RANK_REASON The item discusses a common biological trait and corrects a widely held misconception about its genetic basis, fitting the definition of commentary on a scientific topic.
AI-generated summary · Google Gemini · from 1 sources. How we write summaries →
