© 2015 W. H. Freeman and Company

CHAPTER 1The Genetics Revolution

Introduction to

Genetic AnalysisELEVENTH EDITION

Introduction to

Genetic AnalysisELEVENTH EDITION

Griffiths • Wessler • Carroll • Doebley

CHAPTER OUTLINE1.1 The birth of genetics

1.2 After cracking the code

1.3 Genetics today

Gregor Mendel is the Father of Genetics

Each cell of an organism has a complement of DNA

DNA is biological information

Complementary base pairing

The nuclear genome

Chromosomal DNA is wrapped around histones

Chromosomal condensation by further coiling

Structural comparison of the genome components of eukaryotes, prokaryotes, and viruses

Transcription and translation in a eukaryote

Central Dogma of Biology

Gene polymorphismsThe stuff of genetic variation

1 locus (monogenic)2 different alleles 3 combinations possible

Question

In the diploid cells of an organism, there can be _________ different allele(s) of a given single-copy nuclear gene.

a) only oneb) one or twoc) one, two, three, or fourd) many

Question

In a population, there can be _________ allele(s) of a given single-copy nuclear gene.

a) only oneb) one or twoc) one, two, three, or fourd) many

Question

When referring to two homologous chromosomes in an individual diploid cell, which of the following statements is most accurate?

a) These chromosomes will normally carry the same genes, in the same order.b) These chromosomes will normally be identical in sequence.c) These chromosomes will normally carry the same genes, but often not in the same order.d) All of the above.

Two different genetic approaches

Forward genetics (from phenotype to gene)•ID the mutant phenotype•ID morphological, physiological, developmental differences•ID the gene (DNA sequence)

Reverse genetics (from gene to phenotype)•ID a gene•Mutate, knockout or over-express the gene•Analyze morphological, physiological, or developmental effects (the phenotype)

Question

Experiments where researchers knock out a target gene in a model organism and analyze the effects of this manipulation to get clues regarding the function of the target gene are examples of

a) classical genetics.b) developmental genetics.c) forward genetics. d) mendelian genetics.e) reverse genetics.

Some organisms used as models in genetic research

Model Systems-pp.793-809Be prepared to present to the class the model system whose genus

name begins with the letter closest to the first letter of your last name.

Arabidopsis thaliana

Drosophilia melanogaster (fruit fly)

Saccharomyces cerevisiae (yeast)

Neurospora crassa (fungi)

E. coli (bacteria)

C. elegans (worm)

Mus musculus (mouse)

Genetics today

• Classical genetics and breeding

• Medical genetics and genomics (diseases)

• Plant genetics and genomics

• Genetics, adaptations, and evolution