Genetics Chapter 3

Question 1

Mendels Law of Segregation

Answer 1

every individual possesses two alleles and only one allele is passed on to the offspring

Question 2

Codominance

Answer 2

When both alleles are fully expressed

Question 3

Polygenetic

Answer 3

Traits Controlled by more than one gene

Question 4

Pleiotrophy

Answer 4

One gene affecting multiple traits

Ex. Sickle cell anemia affecting red shaped blood cells and anemia

Question 5

Epistasis

Answer 5

when one gene controls the expression of another

Question 6

Polymorphic

Answer 6

More than just two possible alleles in the population

Question 7

Penetrance

Answer 7

Some genes are not expressed and only expressed at a certain level

Question 8

Incomplete Dominance

Answer 8

Blend

Question 9

Codominant

Answer 9

Both phenotypes apparent

Question 10

Bombay Allele

Question 11

law of independant assortment

Answer 11

inheritance of one trait does not affect the inheritance of a second traits.

Example. inheriting a particular allele for eye color does not affect the ability to inherit any other allele for hair color

Question 12

law of dominance

Answer 12

receive alleles are often broken

Question 13

Gene

Answer 13

a section of DNA responsible for a trait.

ex. gene responsible for eye color

Question 14

Allele

Answer 14

variant form of gene

ex. gene for eye color can have alleled for brown eyes or blue eyes.

Question 15

Chromosomes

Answer 15

contains many genes (X shape)

Question 16

Cystic Fibrosis, sickle cell anemia , hemophilia A

Answer 16

Due to the allele encoding a defective protein(loss-of-function-allele) or that isn’t express at all (null allele)

Question 17

homologous

Answer 17

Simillar chromosome , different alleles

think back: homologous to analogous –> similar ancestor same parts diff functions vs. similar functions but no common ancestor

Question 18

reciprocal recessive epistasis

Answer 18

2 genes need to be expressed for the trait to be expressed.

both genes must have at least one dominant allele for the trait to be expressed.

f2 ratio 9:7 (dom to recessive)

Question 19

Achondeoplasia

Answer 19

a genetic disorder affecting bone growth leads to a common form of dwarfism.

Question 20

heterozygote advantage

Answer 20

ex. genetic diseases are caused by recessive alleles. Usually removed from population through natural selection.

except for, SICKLE CELL AMENIA

Question 21

Balancing Selection

Answer 21

gene brings some advantages to ‘make up’ for its lethal ness..in this case, sickle cell hosts have resistance to malaria