Video 4 - Advanced Genetics

What is mitochondrial DNA and why is it significant?

Mitochondrial DNA is DNA found within the mitochondria, passed from mother to offspring, allowing for the tracing of evolutionary history.

What are linked genes?

Linked genes are genes that are found on the same chromosome and tend to be inherited together, affecting inheritance patterns.

What is the concept of independent assortment in Mendelian genetics?

Independent assortment means that genes assort independently of one another, so the inheritance of one gene does not affect another.

How does the location of genes on chromosomes affect genetic traits?

Genes located on the same chromosome can be linked and inherited together, complicating simple Mendelian inheritance patterns.

What is polygenic inheritance?

Polygenic inheritance involves multiple genes influencing a single trait, leading to a range of phenotypes, such as height.

Give an example of a trait that is influenced by multiple genes.

Height is influenced by multiple genes, resulting in a continuum of possible heights.

What is the significance of crossing over during meiosis?

Crossing over can separate linked genes on the same chromosome, increasing genetic diversity.

How do the odds of rolling a seven with two dice illustrate polygenic inheritance?

Rolling a seven can occur in multiple combinations, similar to how multiple genes can combine to influence a single trait.

What is the role of sex chromosomes in inheritance?

Sex chromosomes can affect inheritance patterns, as seen in traits like color blindness, which is linked to the X chromosome.

What did Mendel study to develop his theories?

Mendel studied seven characteristics of pea plants, including stem length, seed color, and flower color.

What is an example of traits that are often inherited together due to their chromosomal location?

Red hair and freckles are often inherited together because they are located close to each other on the same chromosome.

What is non-nuclear transfer in genetics?

Non-nuclear transfer refers to the inheritance of DNA found outside the nucleus, such as mitochondrial or chloroplast DNA.

How does the Punnett square apply to polygenic traits?

Punnett squares can illustrate the combinations of alleles for polygenic traits, but the complexity increases with more genes.

What is the relationship between the number of genes and the variability of a trait?

The more genes involved in a trait, the greater the variability and range of phenotypes observed.

What is the significance of Mendel's choice of traits for his experiments?

Mendel's choice of traits that assort independently allowed him to establish foundational principles of genetics.

How does the concept of linked genes challenge Mendelian genetics?

Linked genes challenge Mendelian genetics by showing that some traits do not assort independently due to their proximity on chromosomes.

What is the expected outcome of a Punnett square for two individuals with multiple genes?

The outcome will show a greater number of possible combinations than for single-gene traits, reflecting polygenic inheritance.

What is the impact of maternal inheritance on mitochondrial DNA?

Mitochondrial DNA is inherited maternally, meaning all offspring receive it from their mother.

What is the importance of understanding non-Mendelian genetics?

Understanding non-Mendelian genetics is crucial for comprehending complex inheritance patterns and evolutionary relationships.

How can the study of giraffes illustrate non-Mendelian genetics?

The phylogenetic tree of giraffes shows how mitochondrial DNA can reveal evolutionary relationships beyond simple Mendelian traits.

What does a bell-shaped curve in a trait indicate?

It indicates that the trait is influenced by multiple genes, rather than a single gene.

Who discovered sex linkage in genetics?

Thomas Hunt Morgan

What is an example of a sex-linked trait in humans?

Color blindness, which is more common in males due to the presence of a single X chromosome.

How is color blindness inherited?

It is inherited through the X chromosome, with males having a higher likelihood of being color blind due to having only one X chromosome.

What is the probability of a girl being color blind if her mother is a carrier?

1 in 100, due to the need for both X chromosomes to carry the color blindness gene.

What is non-nuclear inheritance?

Inheritance of genetic material that occurs outside the nucleus, such as mitochondrial DNA.

How is mitochondrial DNA inherited?

It is passed maternally from mother to offspring, without crossing over or meiosis.

What is an example of a sex-linked genetic disorder?

Hemophilia, which is more common in males due to its location on the X chromosome.

Why is it difficult to perform Punnett squares for polygenic traits?

Because polygenic traits involve multiple genes, leading to complex inheritance patterns.

What does it mean if a trait is described as having a 'multi-gene' influence?

It means that the trait is controlled by more than one gene, resulting in a range of phenotypes.

What is the significance of linked genes?

Linked genes are genes that are located close together on the same chromosome and tend to be inherited together.

What is the expected outcome when two average height individuals have offspring?

The probability of producing very tall or very short offspring is low, with most offspring being of average height.

What is the role of the X chromosome in sex-linked traits?

The X chromosome carries genes that can lead to sex-linked traits, with males having only one X chromosome.

What is the genetic makeup of a color-blind male?

A color-blind male has one X chromosome with the color blindness gene and one Y chromosome.

How does the presence of an extra X chromosome affect females regarding sex-linked traits?

It provides a backup copy of genes, reducing the likelihood of expressing recessive sex-linked traits.

What is the probability of a male being color blind?

Approximately 1 in 10 males are color blind.

What is the difference between nuclear and non-nuclear DNA?

Nuclear DNA is found in the nucleus, while non-nuclear DNA, such as mitochondrial DNA, is found outside the nucleus.

What can mutations in mitochondrial DNA help trace?

They can help trace evolutionary history and lineage.