Processes of Evolution & GeneticsPart 2

Learning Objectives

1. Describe the importance of DNA replication2. Describe the mechanisms of inheritance at a cellular level

1. Explain the link between meiosis and Mendelian genetics2. Explain the evolutionary significance of meiosis

3. Illustrate an understanding of terms associated with evolutionary biology and genetics through defining and/or describing the terms

4. Distinguish between different forms of gene expression1. Illustrate an understanding of different forms of gene

expression through trait examples and visual diagrams

DNA Structure DNA = Deoxyribonucleic Acid

____________________________________

Discovered by:James Watson & Francis

Crick unlocked structure and Function of DNA

Revolutionized science

DNA Structure• DNA composed of chains of nucleotides. Each nucleotide,

in turn, is made of :• 1. • 2. • 3.

• Double helix is a _____________________

• DNA Bases: ___________________________

DNA Replication

• Why Replicate? • 1.

• 2.

• 3.

Chromosomes• Chromosomes: ___________________________• Contain hereditary genetic information

Chromosomes

• Two Basic Forms:• 1. • ___________

• 2. • ___________• ___________

X Chromosome

Y Chromosome

Chromosomes Somatic cells: __________________

Each pair - same genes _______________________________

Locus (pl., loci):

Allele:

Chromosomes

Mutation

• Changes to the _______________• _____________________________________

• Is one of the _________________________

• Is the only source of __________________

• When does a mutation occur?• _________________________

Mutation - Demonstration

Cell Division

• Source of Genetic Diversity Cell division and differences in division have evolutionary significance

• Only two types of cell in our bodies:• Somatic cells: such as hair, skin, liver, heart, muscle

tissue, etc

• Sex cells (gametes): egg, sperm

Mitosis: Somatic Cell Division

DNA replicates; Parent cell now has full set of chromosomes (23 pairs = 46 chromosomesReplicated

DNA lines up in middle of cell

During division DNA separates. One complete complement goes into one new cell, and the other into the second new cell

Each new cell has full set of DNA

Meiosis• Meiosis: development of ________________

• Only occurs in the testes and ovaries produce __________

• Sex cell division – daughter cells contain _______ ___________________________

• Meiosis involves __________________

Meiosis

Parent cell is diploid Begins

like mitosis; DNA replicated

DNA lines up at middle of cell

Cell divides & DNA separates, creating two diploid daughter cells

2nd cell division: each daughter cell splits into two more cells, and paired chromosomes are split

Each new cell has 23 chromosomes BUT NO PAIRS

Differences

• 1. • 2. • 3.

• Make sure that you can not only names these differences but can also describe them

Evolutionary Significance of Meiosis

• Meiosis – greatly increases genetic variation in a _____________

• ____________________________• (can) produce upwards of 10 billion unique

combinations multiplied by the # of possible combinations for any random mating

Evolutionary Significance of Meiosis

Evolutionary Significance of Meiosis• Linkage• Inheritance pattern in which _________________

______________________• Why? • ___________________________________

• Geneticists calculate linkage percentages

• This is an ____________ to Mendel’s principle of independent assortment

Genes & the Genome

• Gene

• Genome

Genes & the Genome• Polygenic Inheritance • Cumulative effects of ________________

• __________________ contribute• Not ______________________• Expression on a _____________________ (continuous variation) – bell

shaped curve – _________________________

• Examples: Gene

Gene

Gene

Gene

Trait

Genes & the Genome• Pleiotropy• ___________________________________• Primary and secondary results

Gene

Trait

Trait

Trait

Trait

• Norm of Reaction• Table or graph illustrating the possible range of

phenotypic expression for a given genotype• Fruit Fly Example

Gene & the Genome

Environmental Context

• Niche construction• ____________________________________

• Why is this important for biologists, and biological anthropologists, to consider?

• Why should cultural anthropologists and archaeologists pay attention to niche construction?