8.1

Genetic change in bacteria

Can happen by mutation and horizontal gene transfer

Mutation

Changes in existing nucleotide sequences of a cells DNA which is passed to offspring

Vertical gene transfer

Transfer of genes from parent to offspring

Mutants

The modified organisms and progeny

Horizontal gene transfer

Transfer of DNA from one organism to another by a process other than reproduction. This also gets passed down to offspring.

Genotype

The sequence of nucleotides in an organisms DNA. A change in an organisms DNA alters it.

Genotype alterations in bacteria

In bacterial cells, these changes are big bc bacteria are haploid so they have only 1 set of genes and there is no backup. Because of this changes in genotype alters the organisms phenotype.

Phenotype

The observable characteristics of a cell. It can be influenced by the genetic makeup of an organism and environmental factors

Serratia marcescens

Their colonies are red when incubated at 22°C but white when incubated at 32°C. The phenotype change. If the genes responsible for pigment production get removed, both genotype and phenotype changed.

What genetic changes do scientists like to study

The ones that change the microorganisms nutrition requirements.

Auxotroph

A mutant that requires a growth medium

Prototroph 

Mutant that does not require growth medium. Ex. Wild type E.coli

Strain Characteristics

Designated by three letter abbreviation w first letter capitalized.