Mendelian Genetics and Inheritance Patterns

How does Mendel's hypothesis of inheritance differ from the blending theory of inheritance?

Mendel's hypothesis states that genes come in pairs, inherited from each parent, and are not blended, whereas the blending theory suggests traits mix together.

What is the difference between a character and a trait?

A character is a heritable feature (e.g., flower color), while a trait is a specific variant of that character (e.g., purple or white flowers).

What is true breeding stock?

True breeding stock refers to organisms that are homozygous for a trait, producing offspring with the same trait.

What are the P, F1, and F2 generations in Mendel's pea crosses?

P generation is the parent generation with homozygous traits; F1 generation is the offspring of the P generation; F2 generation results from crossing two F1 individuals.

What concept did Mendel's crosses lead to regarding dominance and recessiveness?

one gene is a visible phenotype (dom) while the other wasn't

What result from Mendel's crosses argued against the blending theory of inheritance?

The F2 generation showed that the recessive gene could reappear in ¼ of the offspring, indicating it was not blended but carried.

What is Mendel's law of segregation?

during gamete formation, the alleles for a trait segregate from each other so that each gamete carries only one allele for each gene. anaphase 1 and 2

How does meiosis explain Mendel's law of segregation?

Meiosis involves random alignment of chromosomes in metaphase and separation in anaphase, leading to independent assortment of alleles.

What is the difference between genotype and phenotype?

Genotype refers to the genetic makeup of an organism, while phenotype refers to the observable characteristics.

What is the result of a monohybrid cross between a1 (red) and a2 (white)?

The genotype result is Aa (heterozygous), and the phenotype is red.

What is the multiplication rule in genetics?

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

How can the multiplication rule determine the probability of being homozygous recessive in a monohybrid cross?

By multiplying the probabilities of producing recessive alleles from both parents.

What is the addition rule in genetics?

The addition rule states that the probability of any two mutually exclusive events is the sum of their individual probabilities.

How can the addition rule determine the probability of being heterozygous in a monohybrid cross?

By adding the probabilities of producing a heterozygote from different combinations of alleles.

What is a testcross?

A testcross is used to determine if an organism with a dominant phenotype is homozygous or heterozygous by crossing it with a homozygous recessive organism.

What is the result of a dihybrid cross between a1 (red) and a2 (white) and b1 (short) and b2 (tall)?

The result includes genotypes AaBb (heterozygous) and phenotypes of short red plants.

What is Mendel's law of independent assortment?

alleles for different genes segregate independently of one another during gamaete formation

What are autosomes?

Autosomes are chromosomes that are not sex chromosomes.

What are sex chromosomes?

XX or XY chromosomes that determine an individual's sex.

What is sex-linked inheritance?

traits determined by genes located on the X chromosome, affecting males and females differently.

What is dosage compensation in genetics?

mechanism that equalizes the expression of X-linked genes in males and females, such as X inactivation in females.

What is the expected outcome of a dihybrid cross if genes a and b are genetically linked?

The expected outcome would show a 3:1 ratio of phenotypes due to the linkage of traits.