Genetics

Question 1

What did Medel do and what principles did he discover?

Answer 1

Tracked visible traits transmission through pea plant generations
He studied one trait at a time, crossed purebred round and wrinkled seeds to get multiple children generations

Priciple of Dominance: dominant allele overrides recessive
Principle of Segregation: alleles form homologous pairs during meiosis then segregate
Principle of Independent Assortment: allele pairs seperate independently, traits are passed on independently of others.

Question 2

How do you use punnet squares to find what fillial generation will be

Answer 2

Gammets (separated from parent into individual alleles) are used as a base for punnet squares.

For F1, you fertilize the gammetes to find genotypes.

For F2, you repeat the steps by self pollinating F1

You display your answer using:
Genotype ratio: homo dominant : hetro : homo resessive
Phenotype ratio: dominant : resessive

Question 3

What if you don’t know genotype of an organism

Answer 3

Test cross the organism with a homozygous resessive individual to see what you get. Based on what you get, you’ll find the genotype

Question 4

Differences between incomplete dominance and codominance. Provide an exampls

Answer 4

In incomplete dominance, the blended or bread phenotypes produce a new different phenotype.

In codominance, both alleles are shown on off spring on the same level.

Question 5

What did Morgan do and what did the discover

Answer 5

Bred white x red flies to produce F1 with all red and F2 with some red, some white 3:1 ratio. The whites in F2 were all male. This led to discovery that X chromosome carried eye color determining gene.

He discovered that sex chromosomes contain sex linked traits on the X chromosome but not the Y. X and Y symbolizes gene but subscripts written on only X not Y cause Y is only present if female

Question 6

Who discovered dihybrid crosses, how, and what does it mean?

Answer 6

Mendel crossed round/yellow seeds with wrinkled/green seeds.

In dihybrid, chromosomes have 2 different allele pairs with seperate independently of each other during Gamage formation

Question 7

What does a pedigree chart show and list the modes of inheritance

Answer 7

It shows inheritance of traits from parents to children like a family tree.

Autosomal dominant: unaffected parents make unaffected child
Autosomal recessive: unaffected parents make affected child
Same definitions for sex dominant and sex resessive