In this lesson, history meets science as students investigate whether an event in the 1860s that limited genetic variation among Navajos may have led to both children of a modern-day Navajo couple being born with a rare genetic disease. To investigate this theory, students will use a basic simulation model to track gene frequencies across multiple generations.
During meiosis, homologous chromosomes (1 from each parent) pair along their lengths. The chromosomes cross over at points called chiasma. At each chiasma, the chromosomes break and rejoin, trading some of their genes. This recombination results in genetic variation.