lecture slides week 3-Genetics/Mendelian

True or false: there must be phenotypic variation the population.

True

True or false: The phenotypic trait must have a genetic basis (be heritable)

Where does variation come from?

Mutations and genetic recombination.

How are traits inherited?

Through the mechanisms of heridity.

What was Gregor Mendel’s major methological contribution to biological science when studying heridity?

Mendel was one of the first scientists to apply mathematics and statistical analysis to answer biological questions.

Define gene

A DNA sequence located at a specific position on a chromosome that codes for a particular phenotypic trait.

Who is James?

My boyfriend, who is stinky and fat

Locus

The specific physical location on a chromosome where a gene is found.

What is the central dogma of molecular biology, and what are its main processes?

It describes the directional flow of genetic information inside living cells.

Describe the flow of genetic information according tto the dogma.

Replication—→ transcription—→ translation

What is replication

Duplicating DNA to make an exact copy

What is translation

Reading the mRNA sequence to assemble amino acids into a protein.

What is a diploid (2N)

Cells containing two copies of each type of chromosome.

What is a haploid

Gametes containing only one copy of each chromosome type.

What is the cellular outcome of mitosis

It’s a process of cell division that produces two daughter cells that are genetically identical to one another. It’s used for growth and tissue development.

What is meiosis

A specialized cell division that produces 4 haploid (1N cells) that are genetically distinct from the parent cell and from one another.

What is Mendel’s First Law

Law of Segregation, defines allele pairs seperate from one another during gamete formation during meiosis so that each haploid gamete carries only one allele per gene.

What is Mendel’s Second Law

Law of Independent Assortment, alleles of two or more different genes assort independently of one another into gametess during meiosis.

The allele recieved for eye color does not affect which allele is received for feather color.

What is codominance

Incomplete dominance, both alleles contribute to the phenotype, producing an intermediate or combined effect in heterozygous individuals.

Describe multiple alleles for phenotypic variation

A single gene has more than two possible allele variants within a population.

Describe epistasis

The expression of one gene is masked, inhibited, or modified by the expression of another gene

What is pleiotropy

A single gene affects multiple, seemingly unrelated phenotypic traits

What are multiple alleles, pleitropy, and epistasis?

1) When the population of a species has more than two alleles to contribute to genetic variation

2) When one single affects multiple unrelated phenotypes

3) When the expression of one gene is masked by another.

What is a polygenic trait, and what type of phenotypic variation does it produce?

A polygenic trait is a single character influenced by the additive effects of multiple distinct genes.

The outcome is that it produces continuous variation rather than discrete categorical classes.

What is an example of a polygenic trait.

In fruit fly thorax length, each added allele contributes a quantitative increment.

What is epigenetics?

Changes in gene expression or cellular phenotype that occur without altering the underlying DNA sequence.