Video 3 - Mendelian Genetics

Who is considered the father of genetics?

Gregor Mendel

What type of plants did Mendel use for his genetic experiments?

Pea plants

What is the first cross in a genetic experiment called?

The P cross or parental cross

What are the offspring of the P cross referred to as?

F1 or filial one

What ratio of purple to white flowers did Mendel observe in his second cross?

A 3 to 1 ratio

What does Mendel's Law of Segregation state?

Each allele segregates independently during gamete formation, resulting in a 50% chance of inheriting either allele.

What does Mendel's Law of Independent Assortment state?

Genes for different traits assort independently of one another during gamete formation.

What is a Punnett square used for?

To predict the genotypes and phenotypes of offspring from a genetic cross.

What is the significance of dominant and recessive alleles in Mendelian genetics?

Dominant alleles mask the effect of recessive alleles in the phenotype.

What is an example of a genetic disorder mentioned in the video?

Huntington's disease

What does the term 'hybrid' refer to in genetics?

An organism that has two different alleles for a trait.

What is the expected phenotype ratio for a monohybrid cross?

3:1 ratio of dominant to recessive traits.

What is the purpose of genetic testing in the context of Mendelian genetics?

To determine the presence of genetic disorders and inform ethical considerations.

What is meant by 'blending' in the context of early genetic theories?

The idea that offspring are a mix of parental traits, rather than distinct genetic contributions.

How did Mendel's findings challenge the blending theory?

Mendel showed that traits can be passed down unchanged and can reappear in later generations.

What is the role of probability in Mendelian genetics?

Probability is used to predict the likelihood of inheriting specific traits based on allele combinations.

What does it mean for traits to assort independently?

The inheritance of one trait does not influence the inheritance of another trait.

What is the significance of the F1 generation in Mendelian genetics?

It represents the first generation of offspring from a genetic cross.

What is the expected genotype ratio from a monohybrid cross of two heterozygous parents?

1:2:1 ratio of homozygous dominant, heterozygous, and homozygous recessive.

What does the term 'allele' refer to?

Different versions of a gene that determine specific traits.

What is the relationship between genes and chromosomes?

Genes are segments of DNA located on chromosomes.

What is the effect of linked genes on inheritance?

Linked genes tend to be inherited together because they are located on the same chromosome.

What is the probability of getting heads on the next coin flip after flipping heads four times?

The probability remains 1 in 2, as past flips do not influence future outcomes.

What do the capital letters represent in genetic traits?

Capital letters represent dominant traits, such as round peas (R) and yellow peas (Y).

What is the difference between heterozygous and homozygous?

Heterozygous means having different alleles (e.g., Rr), while homozygous means having the same alleles (e.g., RR or rr).

What is the phenotype of an organism with the genotype Yy?

The phenotype is the physical appearance, which would be yellow in this case.

How do you determine the probability of offspring traits using a Punnett square?

By setting up a Punnett square with the parents' alleles to visualize possible combinations.

What is the probability of obtaining wrinkled seeds from a cross of round seeds (Rr)?

There is a 1 in 4 probability of getting wrinkled seeds (rr).

What is the probability of producing green seeds from a cross of yellow (Yy) and yellow (yy) seeds?

There is a 1 in 2 probability of producing green seeds (yy).

How do you calculate the probability of two independent genetic events occurring together?

Multiply the probabilities of each event together.

What is Huntington's Disease?

A dominant genetic disorder causing degeneration of nerve fibers, leading to uncontrollable shakes and eventual death.

Why is Huntington's Disease considered an ethical issue?

Because individuals may not know they carry the gene until middle age, impacting their decisions about family planning and insurance.

What does a pedigree chart represent?

A pedigree chart shows the inheritance patterns of traits or diseases through generations.

What do squares and circles represent in a pedigree chart?

Squares represent males, and circles represent females.

What does a horizontal line between a square and a circle indicate in a pedigree chart?

It indicates that the individuals had offspring.

What is the significance of the 'big H' and 'little h' in the context of Huntington's Disease?

Big H indicates the presence of the Huntington's gene, while little h indicates its absence.

What is the probability of passing on a dominant trait like Huntington's Disease?

There is a 1 in 2 probability of passing on the trait to offspring.

What is the role of genetic testing in relation to Huntington's Disease?

Genetic testing can determine if an individual carries the Huntington's gene, influencing life decisions.

What is the Law of Multiplication in genetics?

It states that the probability of two independent events occurring together is the product of their individual probabilities.

What is the phenotype of an organism with the genotype RR?

The phenotype would be round, as it is homozygous dominant.

What does it mean if an organism is heterozygous for a trait?

It means the organism has one dominant and one recessive allele for that trait.

What is the expected phenotype ratio from a monohybrid cross?

The expected ratio is typically 3:1 for dominant to recessive phenotypes.

How does the environment influence genetic traits?

While genetics determine potential traits, environmental factors can affect the expression of those traits.

What is the significance of dominant and recessive alleles in genetics?

Dominant alleles mask the effects of recessive alleles in heterozygous individuals.

What is a monohybrid cross?

A genetic cross that examines the inheritance of a single trait.

What is the purpose of using a Punnett square?

To predict the genotypes and phenotypes of offspring from parental crosses.

What is the expected outcome of a cross between two heterozygous parents (Rr x Rr)?

The expected genotypic ratio is 1:2:1 (RR:Rr:rr).