107Meiosis - Dr. Potter MEIOSIS Genetic variation, which is...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Dr. Potter MEIOSIS Genetic variation, which is necessary for adaptation, cannot result from mitosis (asexual reproduction). Sexual reproduction, which mixes genetic information from 2 parents, does provide the genetic variation necessary for evolution. Sexual reproduction consists of meiosis (gamete formation), fertilization (union of egg and sperm) and development (via mitosis) of the zygote. Again, you will need to study the diagrams in the text. Meiosis has 1 DNA replication and 2 cell divisions. Meiosis I is the more important of the 2 divisions. The starting point for prophase I is exactly the same as for mitosis - DNA replication has produced sister chromatids attached at the centromere. Many events occur in prophase I, the most important of which is synapsis forming tetrads, which leads to crossing- over (the first source of genetic variation). At this stage, are the sister chromatids identical or not? Crossing-over must involve the exchange of equivalent pieces of DNA between non-
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 2

107Meiosis - Dr. Potter MEIOSIS Genetic variation, which is...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online