Lecture 4 - Behavioral Genetics

Behavior is a result of…

Genotype, environment, and gene-environment interactions

Innate Behaviors:

Behaviors that are…

1. Performed the same way each time

2. Fully expressed when first exhibited

3. Present in isolated individuals

Reflex:

Involuntary movement responding to stimulus

Fixed Action Pattern

Behavior with no variation, and cannot be stopped once started

Genotyping:

Determining differences in genetic makeup through DNA

Polymerase Chain Reaction (PCR):

Amplifies sections of DNA, making it easier to study

Gel Electrophoresis:

Process of separating out DNA fragments by running a magnetic field through gel

Helps identify specific genetic markers

Single Nucleotide Polymorphism (SNP):

Identifies tiny differences in genetic code between individuals.

Helps identify specific traits + disease susceptibility

Real-Time PCR (qPCR)

Measures the amount of genes actively being transcribed in a sample

Imagine you're a scientist in Jurassic Park, and you've just discovered an ancient mosquito preserved in amber.You suspect it might have dined on dinosaur blood. To confirm this, you need to amplify the tiny amount of DNA that might be in the blood from the mosquito's last meal. Which genotyping method would be best to use?

PCR

An entomologist is curious about the genetic diversity within a beehive. He wants to compare the lengths of DNA fragments related to different roles in the hive. Which method will help him sort these DNA pieces?

Gel electrophoresis

DNA Sequencing:

Reading the order of nucleotide bases to determine genetic information

Scientists have discovered that certain whales have unique patterns in their songs. They believe these variations might be linked to differences in their DNA sequences. To explore this possibility, which method would be best to read the order of bases in the whale DNA?

DNA sequencing

In a rare species of parrots,twins are common, but each pair of twins has distinct behaviors.Researchers want to detect the slight genetic differences that might explain these unique behaviors. What genotyping technique should they use?

Single Nucleotide Polymorphism

Pigeons harbor a remarkable trait where both parents have the ability to produce 'crop milk,' a nutrient-rich substance to feed their chicks. Researchers are fascinated by the hormonal cues in the pigeon's brain that trigger this lactation-like process. To investigate which genes are activated in the brain during lactation and gain insights into the timing and hormonal control of this behavior, what genotyping technique should be applied?

Real-Time PCR

Microsatellites:

Repetitive DNA sequences that frequently mutate

Useful for detecting variation in alleles

What are the statistical methods of analyzing behavior?

Genome-wide association studies (GWAS) and Quantitative Trait Loci (QTL) mapping

What are the molecular methods of studying behavior?

Gene editing

Genome-Wide Association Studies (GWAS):

Analyzes large, genetically diverse populations of unrelated individuals

Identifies genetic variants associated w/traits

Quantitative Trait Loci (QTL) Mapping:

Analyzes gene number and location to determine what region of the genome influences QTLs

Quantitative Trait Loci (QTL):

DNA containing genes that that influence a trait/behavior

Does QTL Mapping involve the study of related individuals or non-related individuals? Why?

Related individuals, as this reduces genetic complexity and makes it easier to link phenotypes to DNA

Does Genome-Wide Association Studies track genetic inheritance patterns?

No, because it analyzes unrelated individuals

Gene editing:

Allows you to change the genome at a precise location

What is the knockout method of gene editing?

Disabling a gene to determine its function

What is the CRISPR-Cas9 method of gene editing?

Deleting, adding, or altering a sequence of DNA to determine its function

How can stress disrupt the HPG axis?

Stress increases the release of GnIH

What is bioinformatics?

Analysis of genetic information to uncover the functions, relationships, and evolutionary histories of genes

What are “Big Data”?

Extremely large data sets requiring specialized analytical tools

What is transcriptomics used for?

To study the amount of gene activity (RNA transcription) in a certain tissue

What is transcriptomic assembly?

A catalog of all RNA transcription (gene activity) at a specific time

What is an MA plot?

A visual diagram that depicts the difference in gene expression between two samples

What are the pros/cons of transcriptomic analyses?

Pros: Gives a wide variety of information on all of the hormones involved in a particular pathway

Cons: Not as targeted as qPCR analyses

How does the HPG axis function?

1. Hypothalamus releases GnRH (Gonadotropin)

2. Gonadotropin tells the Pituitary to release FSH (Follicle Stimulating Hormone) and LH (Luteinizing Hormone)

3. LH signals gonads to release testosterone

What is bioinformatics used for?

Sequencing genomes, analyzing protein/gene expression, comparing genetic data across species