© 2015 W. H. Freeman and Company CHAPTER 1 The Genetics Revolution Introduction to Genetic Analysis ELEVENTH EDITION Introduction to Genetic Analysis ELEVENTH EDITION Griffiths Wessler Carroll Doebley

CHAPTER OUTLINE 1.1The birth of genetics 1.2After cracking the code 1.3Genetics 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 polymorphisms The 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 one b) one or two c) one, two, three, or four d) many

Question In a population, there can be _________ allele(s) of a given single-copy nuclear gene. a) only one b) one or two c) one, two, three, or four d) 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 Be 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