Genetics, Domestication, and Kin Selection: Fox Breeding, Chromosomes, and Inclusive Fitness

Why are Belyaev's breeding experiments with foxes useful for demonstrating the genetic basis of friendly behaviors?

They show that selectively breeding non-scared foxes leads to both behavioral and physical changes, making them more 'puppy-like'.

What physical changes are observed in domesticated foxes due to selective breeding?

Flipped ears, curled tails, multicolored coats, smaller teeth, and thinner bones.

What is Dr. Fitch's explanation for the changes observed in domesticated animals?

Changes occur because adrenal glands slow down development, decreasing fear and stress, which also affects other cell developments.

What is the total number of chromosomes in humans?

Humans have 46 total chromosomes.

How many homologous pairs of chromosomes do humans have?

Humans have 23 homologous pairs of chromosomes.

Why are chromosomes organized in homologous pairs?

Each member of a pair comes from one parent, ensuring genetic diversity.

What percent of the genome is shared between a cell at the top of the page and one of the daughter cells at the end of meiosis I?

50% of the genome is shared.

At the end of meiosis II, what percent of the genome is shared between two gametes from different daughter cells?

Approximately 25% of the genome is shared.

Who has higher inclusive fitness: Dr. Archie or Dr. McLachlan?

Neither; both have the same inclusive fitness of 0.5.

What is the formula for calculating inclusive fitness?

Inclusive fitness = direct fitness + indirect fitness.

If you commit an altruistic act that costs you one offspring, how many first cousins do you need to save for this act to be supported by Hamilton's rule?

You must save at least 4 first cousins.

What is the relationship coefficient (r) between you and a first cousin?

The relationship coefficient (r) is 0.125.

What is the relationship coefficient (r) between you and an aunt/uncle?

The relationship coefficient (r) is 0.25.

What is the calculation for indirect fitness when saving first cousins?

Indirect fitness = (# of first cousins)(r) = (#) x 0.125.

What does Hamilton's rule state regarding altruistic acts?

An altruistic act is supported if the cost to the altruist is less than the benefit to the relatives multiplied by their relatedness.

What is the direct fitness calculation for Dr. Archie?

Direct fitness = 0 x 0.5 = 0.

What is the indirect fitness calculation for Dr. McLachlan?

Indirect fitness = (1 x 0.25) + (2 x 0.125) = 0.5.

What is the direct fitness calculation for Dr. McLachlan?

Direct fitness = 0 x 0.5 = 0.

What is the total inclusive fitness calculation for Dr. McLachlan?

Inclusive fitness = 0 + 0.5 = 0.5.

What happens to the adrenal glands in selectively bred foxes?

They slow down, decreasing fear and stress.

What is the significance of physical traits in domesticated foxes?

They reflect the behavioral changes resulting from selective breeding.