Mendelian Genetics

Question 1

What are the conclusions of Mendel’s experiment

Answer 1

There are alternate versions of ‘heritable units’ that can be passed to the decendants: alleles
An organism receives two copies(two alleles) of any gene from each parent
Some alleles are dominant
The law of segregation: occurs during meiosis

Question 2

Law of segregation

Answer 2

The two alleles for a heritable character segregate/separate during gamete formation and end up in different gametes

Question 3

Phenotype

Answer 3

This is the observed trait of a characteristics derived from a genotype

Question 4

Genotype

Answer 4

This is the genetic makeup that produces a phenotype

Question 5

Homozygote

Answer 5

Two identical alleles for a particular gene

Question 6

Heterozygote

Answer 6

Two non-identical alleles for a particular gene

Question 7

Monohybrid

Answer 7

We are only following one character

Question 8

Test Cross

Answer 8

Used to determine whether an individual displaying a dominant trait is heterozygous or homozygous

Question 9

How is test cross determined

Answer 9

You cross the ‘known genotype’ with the ‘dominant phenotype= e.g. PP or Pp)’

Question 10

Dihybrid Crosses

Answer 10

Follow two characters at once

Question 11

True breeding are always homozygous. True/False

Answer 11

True

Question 12

True breeding

Answer 12

The parent will produce offsprings that are always homozygous

Question 13

Law of independent assortment

Answer 13

Two or more genes assort independently into gametes = The alleles a gamete receives from one gene does NOT influence the alleles a gamete receives for the other gene

Question 14

Incomplete dominance

Answer 14

When a dominant allele isn’t sufficient to mask a recessive allele. The trait doesn’t really overwhelm the recessive trait

Question 15

Co-dominance

Answer 15

When both allele is expressed to give a unique phenotype. For example blood group

Question 16

When there is more than two allelic forms of a given gene dominance hierachy occurs. True/ False

Answer 16

True

Question 17

Pleiotropy

Answer 17

When one gene affects many different phenotypes

Question 18

Penetrance of trait

Answer 18

The frequency(percentage) in which a specific phenotype is expressed by individual with a genotype known to cause the trait
or
not all individuals with a genotype display a corresponding phenotype

Question 19

Expressivity

Answer 19

The degree to which a particular genotype is expressed in the phenotype
or
stronger or weaker versions of a phenotype

Question 20

Epistasis

Answer 20

the phenotypes produced by alleles of one gene is dependent on the phenotype produced by alleles of a different gene
simple definition: The alleles of one gene may mask or conceal the alleles of another gene( some are genetically linked)
involves multiple genes

Question 21

Polygenic Inheritance

Answer 21

Characteristics are controlled by a number of different traits
Traits forma phenotypic spectrum
Quantitative
e.g. Height, skin color (the genes in skin color are incompletely dominant), eye color and risk of diseases

Question 22

Lethal Alleles

Answer 22

Some genes have alleles that prevent survival when homozygous or heterozygous

Question 23

What happens if a trait is dominant

Answer 23

An offspring displaying that trait will always have a parent with that trait

Question 24

What does a square and circle symbolize in pedigree

Answer 24

A square symbolizes males, and a circle symbolizes females

Question 25

What happens if a trait is recessive

Answer 25

An offspring displaying that trait can have parents that don’t display the trait

Question 26

Lethality is recessive, even though the color phenotype is dominant. True/ False

Answer 26

True

Question 27

People with huntingtin’s disease is an example of someone that has a dominant lethal allele. Fact