NGSS HS-LS3-2: Make and defend a claim based on evidence that inheritable genetic variations may result from: (1) new genetic combinations through meiosis, (2) viable errors occurring during replication, and/or (3) mutations caused by environmental factors.
Gather evidence from the three mechanisms below.
During sperm/egg creation, homologous chromosomes pair up and swap sections, creating entirely new combinations of alleles.
Click segments to swap
Before a cell divides, it must copy billions of DNA bases. The machinery is highly accurate, but rare random mistakes (point mutations) happen.
External factors like UV radiation or chemicals can physically damage DNA, causing mutations that, if in gametes, are inherited.
Click cell to irradiate (UV)