The apple is the fruit of the apple tree, species Malus domestica in the rose family (Rosaceae). It is one of the most widely cultivated tree fruits. The tree originated in Central Asia, where its wild ancestor, Malus sieversii, is still found today. Apples have been present in the mythology and religions of many cultures, including Norse, Greek and Christian traditions. In 2010, the fruit's genome was decoded as part of research on disease control and selective breeding in apple production.
There are more than 7,500 known cultivars of apples. Over 69 million tons of apples are grown worldwide. Many beneficial health effects are thought to result from eating apples; interestingly, there are two known forms of apple related allergies. More interestingly; the seeds of apples contain small amounts of a cyanide compound known as a cyanogenic glycoside. Ingesting small amounts of apple seeds will cause no ill effects, but in extremely large doses can cause adverse reactions. There is one known case of fatal cyanide poisoning from apple seeds; in this case the individual chewed and swallowed one cup of seeds.