Lecture 15: Mendelian Genetics

Question 1

What is a character?

Answer 1

An observable feature or trait
- Ex. Colour, Facial Features

Question 2

What is a trait?

Answer 2

Offsprings share traits with their parents
-Ex. Short or Tall, Light or Dark

Question 3

True or False: Two children from the same parents may not have the exact same skin colour?

Answer 3

True, can be varying shades

Question 4

What is continuous variation? Example?

Answer 4

When traits appear to show a spectrum rather than grouped into discrete catergories
ex. Skin colour, when a caucasian and African American have a child their child will have an intermediate skin colour

Question 5

What did Mendel do different than Darwin?

Answer 5

Darwin was trying to see a pattern with traits that were on a continuous spectrum
Mendel used discrete traits that were not part of a continuous spectrum

Question 6

What did Mendels crossing of wrinkled and round peas show?

Answer 6

1. First generation all peas were round(round is the dominant trait)
2. Second generation: 1/4 peas wrinkled , 3/4 peas round(recessive trait is not lost after the first generation)

Question 7

Genes?

Answer 7

-One from each parent(chosen at random) to give to the progeny

Question 8

Genes vs Alleles?

Answer 8

Genes: DNA sections that code for specific proteins or functional RNA, playing a crucial part in biological functions
Alleles: variations of these genes, leading to diverse traits such as eye color.

Question 9

How many alleles can humans have in each gene?

Answer 9

Two, one from each parent

Question 10

What is homozygous?

Answer 10

-Both alleles are either recessive or dominant(SS or ss)

Question 11

What is heterozygous?

Answer 11

-One of each allele(Ss)

Question 12

How many copies of genes for each character do humans have?

Answer 12

2 genes per character

Question 13

What is the law of segregation?

Answer 13

Segregation of alleles into each gamete

Question 14

What is the phenotype?

Answer 14

The traits an organism shows

Question 15

What is the genotype?

Answer 15

The set of alleles an organism has(not all seen visually)

Question 16

What does the law of independent assortment explain?

Answer 16

The alleles or two or more genes get sorted into gametes independent of each other
ex. skin colour is not impacted by height

Question 17

Can you tell which alleles a homolog has just by looking at it under a microscope?

Answer 17

no

Question 18

Are males heterozygous or homozygous?

Answer 18

Heterozygous(XY)

Question 19

Are females homozygous or heterozygous?

Answer 19

Homozygous(XX)

Question 20

In humans is maleness dominant or femaleness?

Answer 20

maleness

Question 21

First rule of probability?

Answer 21

Two independent events that have no influence on each other, the probability of those two events occurring is the product of each independent event occurring

Question 22

Second Rule of Probability?

Answer 22

Probabilities of mutually exclusive events sum
ex. if the probability of being homozygous round is 1/4 and the probability of being heterozygous round is 1/2 the probability of being either homozygous round or heterozygous round is 3/4