UNH Intro. to Genetics 604 Vocabulary Exam 1

Genetics

How information is transmitted in Biology

Transmission genetics

How genetic information is transmitted from parent to offspring

Molecular-developmental Genetics

How genetic information is transmitted from DNA to gene action

Population Genetics

How genetic information is transmitted over many populations

Blending Theory of Inheritance

Genes are like liquids that blend together

Allele

Different versions of the same gene

Mendel's two conclusions

1. Genes are like particles that do not blend

2. Some Genes are dominant over others

Gene products

Encoded by genes, control traits

Transcription factors

Encoded by genes, control gene expression

Mul1factorial Hypothesis

Continuous traits are encoded by multiple genes in a Mendelian fashion

Tatum and Beadle

one-gene-one-enzyme model

Central Dogma of Molecular Biology

DNA --> RNA --> Protein

Replication

New DNA molecules are made

Transcription

New RNA molecules are made

Translation

New proteins are made

Model organisms

Easy to work with in a lab (ex: fruit flies)

Model organism characteristics

Small, short generation times, small genomes

Pedigree analysis

Tracks inheritance of mutant gene through family history

Genetically modified organisms

Created by inserting a new gene into genome

Kymriah

First FDA approved gene therapy drug - uses T cells to fight cancer

Gene discovery

Finding genes that control individual traits

Mutation

Process that gives rise to new mutants

Forward genetics

1. Start from a pool of random single gene mutants

2. Find the phenotypes of interest

3. Find the mutaGons that cause them

Pure lines

Phenotypes of all selfed offspring identical no matter what generation

Selfing

Self pollination

Monohybrid cross

3:1 phenotype ratio

1:2:1 genotype ratio

Mendel's law of equal segregation

1. A hereditary factor called a gene is necessary for producing pea color

2. Each plant has a pair of this type of gene

3. The gene comes in two forms called alleles

4. A plant can be either Y/Y, y/y, or Y/y

5. In the Y/y plant, the Y allele dominates, and so the phenotype will be yellow

6. In meiosis, the members of a gene pair separate into gametes

7. During fertilization, gametes fuse randomly

8. Equal numbers of each allele are maintained throughout meiosis

Homozygous dominant

Two copies of dominant allele (ex: AA)

Heterozygous

One copy of each allele (ex: Aa

Homozygous recessive

Two copies of recessive allele (ex: aa)

Dihybrid

One copy of each allele for each gene (ex: Aa:Bb)

Dihybrid cross

9:3:3:1 phenotype ratio

Stages of the cell cycle

M = mitosis

S = DNA synthesis

G = gap

Mitosis

2n = 2n + 2n

n = n + n

2 daughter cells

Meiosis

Produces meiocytes that become gametes; 4 daughter cells

Autosomes

All chromosomes BUT sex chromosomes

Sex chromosomes

Determine sex (XX or XY)

Homogametic sex

Female; XX

Heterogametic sex

Male; XY

Autosomal recessive

Phenotype appears in progeny of unaffected parents

Autosomal dominant

If you have one disease allele, you can get the disease; shows up in every generation

X linked recessive

1. Usually present in males

2. None of offspring of affected male show phenotype, but all daughters are carriers

X linked dominant

1. Affected males pass condition to all daughters, no sons

2. Affected heterozygous females mated to unaffected males pass condition to half sons and daughters

Y linked inheritance

SRY gene - testis determining factor, maleness

Product rule

Used to calculate probabilities of mating outcomes

Chi-square test

Used to determine the likeliness of observed results if null hypothesis is true

If < 5%, reject the null

If > 5%, fail to reject the null

X^2=Σ(O-E)2/E

Degrees of freedom

Number of classes minus 1

(ex: for monohybrid cross 1 df;

for dihybrid cross 3 df)

Quantitative phenotypes

Phenotypes varied - normal distribution

Quantitative trait loci

Genes (loci) that control continuous (quantitative) phenotypes (traits)

Mitochondrial DNA

Always passed down from mother

Cytohet

Cells with different organelle genotypes

Recombination map

Chromosome map based on recombination frequencies

Crossing over

Produces new allelic combinations during meiosis

Chiasmata

Chromosome conformations that give rise to crossing over

Double strand break

Physical breakage and rejoining of DNA

Cis

AB/ab

Trans

Ab/aB

Linkage map

Spatial map of genes on chromosome based on recombination frequencies

Genetic map units

Distance between genes for which 1% of meiosis is recombinant

Molecular markers

Sequence variants used to map phenotypes to chromosomal regions

Used to find the genes for traits

Physical maps

Sequence based map of actual genomic DNA

Microsatellites

Small stretches of low complexity repeat sequence

Horizontal transmission

Transferring DNA between individuals of the same generation

Vertical transmission

Transferring DNA from a previous generation

Colony

Derived from a single cell

Cell clones

Bacterial colonies expand clonally

Conjugation

Leads to the formation of new genotypes in progeny; uses pili

Faulty outlooping can lead to plasmids that carry chromosomal DNA

Can then transfer that to other cells

Plasmids

Can sometimes integrate into genome

Transformation

Bacteria can take up DNA from environment

Bacteriophage

Viruses of Bacteria

Can also transfer DNA between cells

Lytic cycle

When bacteriophage turn the bacterial cell into a factory to make more phage

Lysogenic

When bacteria harbors dormant phage

Insertional mutagenesis

Use transposons (mobile DNA elements) to cause mutant phenotype

Can then find gene using sequencing (we know the sequence of the transposon)

Heteroduplex regions

Based on how the cell's DNA repair machinery corrects double strand breaks