Genetics - FINAL - Unit 4

________ create new alleles

Mutations

2 types of mutations

1. Base pair substitutions (SNP’s)

2. Insertion/Deletions (Indels)

Causes of mutations

DNA lesions or Errors in replication

DNA lesions

DNA with a damaged base pair

DNA lesions are ________, with no external cause

Spontaneous

Superoxide dismutase and catalase work together to…

Solve the problem of free radicals

Free radicals

Molecules that are extremely reactive, byproduct of metabolism

Photolyase

Repairs lesions pyrimidine dimers

Excision repair by _________ repairs mutations

endonucleases

4 mutations in transcribed/translated regions

1. Silent mutation

2. Missense mutation

3. Nonsense mutation

4. Frameshift mutation

Silent mutation

Does NOT alter amino acid sequence

Missense mutation

Results in different amino acid

Nonsense mutation

Amino acid codon makes stop codon

Frameshift mutation

Shifts the reading frame set by start codon

Which 2 mutations result in 1 or more incorrect amino acid?

Missense and Frameshift

Mutations in regulatory region can result in…

A gene supposed to be on/off, being on/off

Mutations in non-functional regions…

Have no effect on us

Acquired mutations occur…

Post zygote

2 types of acquired mutations

Somatic mutations and Germinal mutations

Somatic mutations

Mutations in all other cells that do NOT produce gametes

Germinal mutations

Mutations in germ cells (gamete producing cells)

Mutations occur in ___ DNA molecule in ___ cell

1, one

We get inherited mutations from…

Our mom and dad

In inherited mutations, mutations occur in _____, meaning all cells will have it

Zygote

Aberrant euploidy

Having abnormal number of chromosome sets

Monoploid means _ set of chromosomes

1

Monoploid is the same thing as _______

Haploid

Polyploid means ___ ____ ___ set of chromosomes

More than 1

Autopolyploids

Extra pair of chromosomes came from parents

Allopolyploids

Extra pair of chromosomes came from different species via hybridization

Aneuploidy

Missing/extra chromosomes within a single set

Monosomic

Missing from a set

Trisomic

extra in a set

Aneuploidy is caused by ________ (unequal segregation)

nondisjunction

Aneuploidy in humans has autosomal _______ and autosomal ________

monosomics, trisomy

T/F Autosomal monosomics have no chance of survival

True

T/F Autosomal trisomy have no chance of survuval

False

Examples of trisomy are

Down syndrome and Patau & Edwards syndrome

Sex-chromsome aneuploidy results in _______ syndrome, where women are missing their second X chromosome

Turner

Will you have an effect if you have XYY or XXX chromosomes?

No

Age of ________ increases chances of having aneuploidy in humans

Mother

Why doesn’t our father impact chances of anueploidy?

Timing of meiosis

Evolution

Genetic change within a population from one generation to the next

Pre-Darwin, the ______ contemplated evolution

Greeks

Darwin provided ______ and ________ of evolution

Evidence, Mechanisms

What are requirements for evolution?

Evolutionary algorithm

Some individuals produce more offspring than other due to what 2 things?

1. Chance

2. Traits they have

A common misconception is that evolution is…

Just a theory

Scientific theory

Explanation of the mechanisms causing a phenomenon

Microevolution

small scale changes (a few generations)

Macroevolution

large scale patterns due to cumulative effects of microevolution

Adaptive evolution

Produce more offspring because of their traits

Neutral evolution

Produce more offspring because of chance

Diversity

difference within a population

Divergence

difference between a population

Polymorphism

existence of variation in a population

Allelic frequency

frequency of alleles

Genotypic frequency

frequency of genotypes

Mutations _________ genetic diversity

Increase

Gene flow

movement of genes from one population to another followed by reproduction

Gene flow can ______ or ______ allele frequency

Increase, Decrease

Selection

Reproductive success of individuals due to traits

Selection drives _______ evolution

adaptive

Adaptation

traits change and impact survival and reproduction

Selective agent

The thing doing the selecting

Artificial selection

Human chosen

Natural selection

Naturally chosen

2 types of natural selection

Sexual and environmental selection

Sexual selection

Chosen by mate preferences or competition by males

Environmental selection

traits aid in survival

Purifying selection

new mutation reduces reproductive output

Directional selection

change in a trait in one direction over time

Stabilizing selection

traits stay the same over time

A mutation may _______ or ________ reproductive output

Increase, Decrease

Directional and Stabilizing selection only occur in the presence of ________ traits

Complex

Selection increases ______ and _________ frequencies

Allelic, genotypic

Genetic drift

Difference in reproductive success unrelated to traits but due to chance

Genetic drift drives ______ ________

Neutral evolution

Founder effect

Small # of individuals establish a new population

Genetic bottleneck

Reduction in population size due to events, causing loss in genetic variation

Genetic drift can occur by…

Founder effects and Genetic bottleneck

Genetic drift _________ diversity

decreases

4 mechanisms of evolution

1. Gene duplication

2. Genome duplication

3. Horizontal gene transfer

4. Endosymbiosis

3 fates of gene replication

1. Similar function

2. Different function

3. Pseudogenes (loses function)

Genome duplication can happen via ________, followed by gene and chromosomal ________

Polyploidy, evolution

Horizontal gene transfer

Obtaining genes from a different species

Endosymbiosis

1 cell living within another organism

Loss of traits leads to __________

Simplification

2 step process of simplification

1. Relaxation of selection

2. Random mutations in genes/regulatory regions

Relaxation of selection

character is no longer needed

Allopatric speciation

Population divides geographically/physically

Speciation

acquisition of reproductive isolating mechanism

2 mechanisms of speciation

1. Prezygotic

2. Postzygotic

Prezygotic barriers

Prevents fertilization

Postzgotic barriers

Prevents healthy growth

What is the problem of defining species?

No single rule fits all organisms

Macroevolution

Studying patterns following speciation

Lineages

Populations extended over time

What creates lineages?

Speciation

What removes lineages?

Extinction