Unformatted text preview: Chapter 6 part III
Genetic diversity and evolution
Genetic Mutations occur, but infrequently
Diversity through: Independent assortment of chromosomes Makes gametes with new allelic combinations on different
chromosomes Crossing over Makes new combinations on the same chromosome Pair of homologous chromosomes
(the same, but different) It seems like during recombination, the chromosomes
break and reform. Is this true at the DNA level?
break Does DNA break and rejoin during
recombination? Meselson and Weigle – Used viral DNA and
Coinfected E. coli with light and heavy strains of
One batch of growth media contained 13C and 15N
2nd batch contained 12C and 14N
and 14 Separated on a CsCl density gradient What would the test tube look like if:
1.There is no physical breakage and rejoining of DNA?
2.There is breakage and rejoining? (We’’re skipping the “double-strand break
repair” model for recombination)
repair” Clicker: Is it possible to be an XY
female or an XX male?
2. No XY female and XX male
View Full Document