Module 2- Gentics, Linkage, Cell cycle

Question 1

Genotype

Answer 1

• information stored in the DNA
• indirect target of selection

Question 2

Phenotype

Answer 2

• physical representation of the genotype
• Direct target of selection

Question 3

Monogenic Phenotype

Answer 3

One gene affects one phenotype/ Trait

Question 4

Polygenic Phenotype

Answer 4

Many genes affect one phenotype/trait

Question 5

Pleiotropic Phenotype

Answer 5

One gene affects many phenotypes/traits

Question 6

Continuous variation

Answer 6

All values in the phenotypic range can occur

Question 7

Discrete Variation

Answer 7

Traits are differentiable (Color, Number)

Question 8

Phenotypic Variation

Answer 8

results from the interaction between information from the genotype and from the environment

Question 9

Phenotypic Plasticity

Answer 9

the ability for an individual with a specific genotype to express different phenotypes as a result of environmental differences

Question 10

Evolution

Answer 10

Changes in heritable traits in a population over time

Question 11

Natural selection

Answer 11

traits will arise and be passed on to offspring that will increase survival

Question 12

Sexual Selection

Answer 12

The ability to obtain mates

Question 13

Genetic Recombination

Answer 13

crossing over of alleles in meiosis

Question 14

Mutation

Answer 14

Error in genetic replication that causes a large change in an organism

Question 15

Primary sexual selection

Answer 15

Traits that are directly related to sexual reproduction (production of gametes, ability to mate, and nurturing young)

Question 16

Secondary sexual selection

Answer 16

Traits to increase an individuals reproduction
-Intersexual selection: attracting mates
- Intrasexual selection: competing for mates

Question 17

Crossing over

Answer 17

alleles from both parents exchange lengths of their chromosomes

Question 18

Independent assortment

Answer 18

• random distribution of chromosomes/sister chromatids when cells divide in meiosis
• no linkage results in a true breeding test cross having an F2 generation of 1:1:1:1 ratio

Question 19

Homologous chromosomes

Answer 19

nearly identical chromosomes

Question 20

Diploid

Answer 20

Two sets (2n)

Question 21

Haploid

Answer 21

One set (n)

Question 22

Allele

Answer 22

variant of a gene

Question 23

True Breeding

Answer 23

Always give rise to the same genotypes

Question 24

Homozygous

Answer 24

the individual has two of the same alleles for a specific gene

Question 25

Heterozygous

Answer 25

the individual has two different alleles for a specific gene

Question 26

Hybrid cross

Answer 26

crossing of two true breeding lines

Question 27

Law of segregation

Answer 27

during the formation of gametes, genes are randomly separated into the gamete cells

Question 28

Complete Dominance

Answer 28

the dominant allele completely over powers the recessive allele

Question 29

incomplete dominence

Answer 29

heterozygous individuals express a blend of the two phenotypes

Question 30

Semi-dominance

Answer 30

Heterozygous individuals express an exact intermediate between the two phenotypes

Question 31

Co-dominance

Answer 31

a heterozygous individual expresses both phenotypes at once

Question 32

multi-locus crosses

Answer 32

two or more traits are studied in a cross

Question 33

multi-locus cross with two true breeding individuals

Answer 33

F2 generation shows a 9:3:3:1 ratio

Question 34

Additive traits

Answer 34

each allele of a given type adds a certain amount of phenotypic effect

Question 35

Epistasis

Answer 35

one trait determines the expression of another

Question 36

Complete linkage

Answer 36

- linkage results in a true breeding test cross having an F2 generation of 1:1 ratio - There is no recombination of alleles

Question 37

Incomplete Linkage

Answer 37

- some linkage results in a true breeding test cross having an F2 generation of 1:1 ratio of recombinants and a 1:1 ratio non-recombinants

Question 38

high recombination frequency

Answer 38

- Crossovers are essentially certain at a high percent - percent translates to distance apart

Question 39

Aneuploidy

Answer 39

Abnormal number of chromosomes

Question 40

non-disjunction

Answer 40

chromosomes fail to separate in anaphase - Meiosis 1: all gametes are affected - Meiosis 2: only half the gametes are affected