Sources of Genetic Variation
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.
Total Novel Genetic Variations Generated:
Gather evidence from the three mechanisms below.
0
1. Meiosis (Crossing Over)
During sperm/egg creation, homologous chromosomes pair up and swap sections, creating entirely new combinations of alleles.
Click segments to swap
A
B
C
D
a
b
c
d
New Combinations: 0
2. DNA Replication Errors
Before a cell divides, it must copy billions of DNA bases. The machinery is highly accurate, but rare random mistakes (point mutations) happen.
Original Template Strand:
New Copied Strand:
Replication Errors: 0
3. Environmental Mutations
External factors like UV radiation or chemicals can physically damage DNA, causing mutations that, if in gametes, are inherited.
Click cell to irradiate (UV)
Radiation Mutations: 0