3 - Mendelian Genetics - Pedigrees and Autosomal vs Sex-linked Traits and GWAS

AND

Multiply

OR

Add

Genome-Wide Association Studies (GWAS)

An approach used in genetics research to associate specific genetic

variations with particular diseases

How is GWAS done?

Involves scanning genomes from many different people, looking for

genetic markers that can be used to predict the presence of a disease

Single Nucleotide Polymorphisms (SNPs)

A change at a single nucleotide (A, T, C, or G) in the DNA sequence.

Are SNPs a causative mutation?

No, they act as markers “associated with” diseases

Manhattan Plots

A type of scatter plot used in genome-wide association studies (GWAS) to display SNPs (Single Nucleotide Polymorphisms) across the genome and their statistical significance in association with a trait or disease.

DNA Polarity direction

5’ —> 3’

DNA Synthesis Direction

5’->3’

Why is DNA polar?

The asymmetrical chemical structure of its nucleotides and the way they are connected in a strand. This polarity gives each strand a direction—from the 5′ (five-prime) end to the 3′ (three-prime) end.

RNA Polarity direction

5’->3’

RNA Synthesis direction

5’->3’

mRNA

Made during the process of transcription; messenger RNA — it is a type of RNA that carries genetic information from DNA to the ribosome, where proteins are made

tRNA

Used during translation, transfer RNA — it is a small, folded RNA molecule that delivers amino acids to the ribosome during translation, helping build a protein based on the instructions in mRNA.

rRNA

Ribosomal RNA, a non-coding RNA that forms the core structural and functional components of ribosomes

Are prokaryotes polycistronic or monocistronic?

Polycistronic

Are eukaryotes polycistronic or monocistronic?

Monocistronic

Polycistronic

Multiple genes are encoded on a single mRNA molecule and can

Monocistronic

Each monocistronic mRNA has one start codon and one stop codon, leading to the translation of one protein from one mRNA

Transposable elements

Also known as jumping genes, are segments of DNA that can move from one location to another within a genome

Conservative transposition

Transposable element (TE) moves from one location to another in the genome, but without increasing the number of copies of the element

Replicative transposition

Transposable element (TE) makes a copy of itself and inserts that copy into a new location in the genome, while the original copy remains in its original location

Transposons

Mobile DNA sequences that can move from one location to another within the genome

Inverted repeat at ends of transposon…

allows it to recognize its ends in the “jumping” process

Direct repeats

Generated from the host in the transposition process

Horizontal or Lateral Gene Transfer

From species to species- process by which genetic material is transferred from one organism to another without reproduction (i.e., without being inherited from parent to offspring)

How is lateral/horizontal gene transfer identified?

Can be identified by GC content: the GC% is species differ from the average GC content of the recipient organisms genome

Vertical Gene Transfer

Process by which genetic material is passed from parent to offspring.

Endosymbiont Theory

Proposes that mitochondria and chloroplasts in eukaryotic cells originated from free-living prokaryotic bacteria that were engulfed by an ancestral eukaryotic cell, forming a symbiotic relationship.