Figure 2.17b Mendel’s PeasOur Origins, 2nd Edition

Copyright © 2011 W.W. Norton & Company

Mendel and Darwin’s missing evidence

Figure 2.21a Fruit Fly MutationsOur Origins, 2nd Edition

Copyright © 2011 W.W. Norton & Company

Mutation and genetic variability: Morgan’s fruit flies

Human phenotypes

• Most human phenotypic characteristics not expressed as Mendelian alternatives.

• Continuous vs. discrete characters.

Figure 2.1 The Tree of Life

Mitochondria

Somatic tissue

Somatic tissue

Somatic tissue

Somatic tissue

Somatic tissue

Bone

Bone production

Modeling bone

Melanocytes

Somatic tissue

Skin

Gametes

DNA

• Deoxyribonucleic acid

• 1. Nuclear DNA– In nucleus of cell

• + proteins, form a chromosome

– A set of DNA molecules is called a genome.

• 2. Mitochondrial DNA– In mitochondria

• Cytoplasmic organelle

– Inherited from mother only

DNA structure

• Double helix• Basic building block is the nucleotide

– phosphate group + deoxyribose + base• Bases: adenine, guanine, thymine, cytosine• Complementary base pairs: A-T; G-C

DNA function1. replication

Long, thin moleculesAll the DNA in a humanindividual: c. 200 timesthe distance from the Earth to the sun.

Backbone does not vary within or between DNA moleculesSo backbone can be represented by a straight line

Replication: Each of the 2 replicated molecules have 1 parent strand (old)and 1 daughter strand (new)

Complementary base pairing