p arm of a chromosome: The short arm of a chromosome.
The "p" comes from the French "petit" meaning small.
The letter "q" was selected to signify the long arm merely because "q" is the next letter in the alphabet.
也就是说,“p”代表短臂是因为法语单词"petit"的缩写,而长臂用“q”表示仅仅是因为与短臂相对应,Q紧挨着字母P。
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