Lecture 16. The Molecular Basis of Mendelian Genetics

Question 1

What is evolution ?

Answer 1

Descent with modification

Question 2

What is genetics ?

Answer 2

Study of biological inheritance

Question 3

What is a more specific definition of evolution ?

Answer 3

The process by which the genetic material of a population change over time

Question 4

What is population ?

Answer 4

A group of organisms of the same species, in the same region, capable of mating freely with one another

Question 5

What is a character ?

Answer 5

A feature of an organism

Question 6

What is a trait ?

Answer 6

The state of a character in an organism

Question 7

What is a phenotype ?

Answer 7

All the observable traits of an organism. These results from the interaction of its genotype with the environment.

Question 8

What is population genetics ?

Answer 8

Study of the genetic composition of biological populations and changes to this composition

Question 9

What is microevolution ?

Answer 9

Evolution within a species

Question 10

What is evolutionary genetics ?

Answer 10

Broader study of how population genetic phenomena bring about long term evolutionary changes

Question 11

What is macroevolution ?

Answer 11

Evolution above the species level

Question 12

What are the laws that govern biological inheritance ?

Answer 12

1. Inheritance of acquired traits

2. Blending inheritance

Question 13

What is the Weismann barrier ?

Answer 13

Changes that occur in the body/soma cannot be passed on to the germ line

Question 14

What does the weismann barrier show ?

Answer 14

Invalidates Darwin and Lamark theories of heridity but strengthened evolution by natural selection

Question 15

Why was blending inheritance wrong ?

Answer 15

Advantageous traits would be blended away before selection could act

Question 16

What was Mendels particulate inheritance ?

Answer 16

Traits are determined by discrete units that are inherited intact through the generations

Question 17

What are Mendels laws of inheritance ?

Answer 17

1. Law of segregation
2. Law of independent assortment
3. Law of dominane

Question 18

What was Mendel’s idea about heritability ?

Answer 18

Heritability is mediated by discrete units or genes that can have alternate forms or alleles

Question 19

What is the law of segregation ?

Answer 19

During gamete formation, the alleles for each gene segregates from each other so that each gamete carries only one allele for each gene. The allele is chosen randomly

Question 20

What is the law of dominance ?

Answer 20

Some alleles are dominant while others are recessive, an organism with at least one dominant allele will display the effect of the dominant allele

Question 21

What is violation of the law of dominance ?

Answer 21

1. Some alleles do not show simple dominant/recessive relationship - incomplete dominance
2. Codominance

Question 22

What is incomplete dominance ?

Answer 22

Heterozygote phenotypes appear intermediate between the homozygote values

Question 23

What is codominance ?

Answer 23

A new intermediate phenotype, both the recessive and dominant traits appear discretely alongside each other

Question 24

What is the law of independent assortment ?

Answer 24

Genes for different traits segregate independently during gamete formation

Question 25

What is a violation of the law of independent assortment ?

Answer 25

Genes do not always assort independently

Question 26

What are Mendel’s assumptions ?

Answer 26

1. Only two alleles exist for each gene

2. Each trait is controlled by one gene

Question 27

What is the violation to Mendel’s assumption that only two alleles exist for each gene ?

Answer 27

Some genes are multiallelic

Question 28

What is the violation to Mendel’s assumption that each trait is only controlled by one gene ?

Answer 28

Some traits are controlled by multiple genes (polygenic)

Question 29

What is the chromosome theory of inheritance ?

Answer 29

The behaviours of chromosomes during cell division mirrors Mendels Laws

Question 30

What was the conclusion of the chromosomal theory of inheritance ?

Answer 30

Genetic material was contained on the chromosome

Question 31

What is the material of inheritance ?

Answer 31

DNA

Question 32

What is the structure of DNA ?

Answer 32

Double helix

Question 33

What is molecular genetics ?

Answer 33

The study of molecular material of heredity DNA

Question 34

What is DNA replication important for ?

Answer 34

Universal to all life and essential for biological inheritance

Question 35

What is homology ?

Answer 35

Similarity due to common descent

Question 36

What is a mutation ?

Answer 36

An alteration in the DNA sequence

Question 37

What are the two types of mutation ?

Answer 37

1. spontaneous

2. Induced by mutagens

Question 38

What are the major steps in studies of molecular evolution ?

Answer 38

1. Identify homologous sequences

2. Indentify differences between them

Question 39

What do shared mutations act as ?

Answer 39

Markers of shared descent

Question 40

What is the genome ?

Answer 40

The complete set of genetic informationin an organism

Question 41

What is chromosomal crossover ?

Answer 41

The production of gametes via meiosis involving genetic crossover

Question 42

What does recombination promote ?

Answer 42

Independent assortment

Question 43

What is linkage ?

Answer 43

The closer two genes are on a chromosome the less likely a recombination event will occur between then