Genetics

Chromosome

염색체

Definition

A thread-like structure of tightly coiled DNA and proteins found in the nucleus, carrying genetic information.

Detailed Explanation

Humans have 46 chromosomes arranged in 23 pairs; the sex chromosomes (XX in females, XY in males) differ between sexes. Chromosome number varies enormously across species — dogs have 78, ferns can have hundreds. Errors in chromosome number during meiosis cause conditions like Down syndrome (trisomy 21). Chromosome structure changes — inversions, translocations — can drive reproductive isolation and thus contribute to speciation.

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