Lecture 7: Microevolution & Mutation

Question 1

allele frquency

Answer 1

• the # of times an allele occurs in the population

- represented as a proportion of the whole(typically in decimal form)

Question 2

population

Answer 2

• a group of individuals from a single species

- genes are all the same but alleles probably differ

Question 3

what are the microevolutionary forces?

Answer 3

• gene flow
• non-random mating
• genetic drift
• mutation
• selection

Question 4

microevolution

Answer 4

-factors that cause evolution are very slow and which results in evolution taking a long time

Question 5

gene flow

Answer 5

• the movement of alleles from one population to another

- aka migration

Question 6

does gene flow increase or decrease genetic variation?

Answer 6

-increase

Question 7

non-random mating

Answer 7

-if a population does not mate at random but instead mate with a select number of individuals, the mixing of genotypes is not random

Question 8

assortative mating

Answer 8

• organisms of similar phenotype mate more often than expected by random chance
• tends to inc. the frequency of homozygotes in the population

Question 9

self-fertilization

Answer 9

-the fusion of sperm and egg that produced by same plant

Question 10

does non-random mating increase or decrease genetic variation?

Answer 10

-decrease

Question 11

genetic drift

Answer 11

• any random change to the allele frequency of a opoulation due to a chance event
• greater impact on a small population than a large one

Question 12

founder effect

Answer 12

• an event caused a small population to go to a new to a new island
• animals are the “founding fathers”

Question 13

bottleneck effect

Answer 13

• an event occurred on the species’s original island and only a few survivors remain
• shrinking of a population

Question 14

how are founder and bottleneck effects different?

Answer 14

-same result, different cause to make the result

Question 15

mutation

Answer 15

-ultimate source of genetic variability

Question 16

where do new genes come from?

Answer 16

-mutations

Question 17

crick and brenner’s experiment and results

Answer 17

• the reading frame (sequence of codons) of a gene could be destroyed by mutation and then restored
• if the total number of deletions or additions were multiples of 3

Question 18

degenerate code

Answer 18

-more than one codon codes for the same amino acid

Question 19

reading frame

Answer 19

-refers to how the nucleotides in a nucleic acid molecule are grouped into codons, with each codon containing 3 nucleotides

Question 20

frameshift mutation

Answer 20

• a genetic mutation caused by insertions/deletions of a number of nucleotides in a DNA sequence that is not divisible by 3
• when the reading frame has shifted

Question 21

chromosome level mutations

Answer 21

-involves changes in entire chromosomes, either in number or structure

Question 22

nondisjunction

Answer 22

• occurs when chromosomes fail to separate during Metaphase 1
• the result is a gamete with a missing chromosome or with an extra chromosome

Question 23

aneuploidy

Answer 23

-a gamete or individual has gained or lost a chromsome

Question 24

monosomy

Answer 24

-a nondisjunction in meiosis, where a cell’s chromosome was pulled from it, and has one instead of two

Question 25

trisomy

Answer 25

-a nondisjunction in meiosis, where a cell pulled an extra chromosome, and has three instead of two

Question 26

polyploidy

Answer 26

- where the entire genome is copied - result of either a meiotic error where none of the homologs separate and they all go to one daughter cell OR due to a hybridization event btwn 2 different species that're similar

Question 27

ploidy

Answer 27

-number of copies of chromosomes

Question 28

what are the outcomes of mutations?

Answer 28

- harmful (most common) - neutral (most common) - beneficial

Question 29

harmful outcomes of mutations

Answer 29

- lethal | - minor to major effects

Question 30

neutral outcomes of mutations

Answer 30

- silent or chromosomal inversions - non-coding regions of DNA - no fitness loss (lead to changes in phenotype that don't really hinder the organisms ability to survive

Question 31

types of point mutations

Answer 31

- silent mutation - missense mutation - frame shift mutation - nonsense mutation

Question 32

types of chromosomal mutations

Answer 32

- deletion | - duplication

Question 33

silent mutation

Answer 33

- one nucleotide switches | - result: exact same amino acid is translated

Question 34

missense mutation

Answer 34

- occurs when the substitutions lead to the replacement of one amino acid with another - changes the protein, often has minimal affects on a protein's fuctioning

Question 35

nonsense mutation

Answer 35

- lead to the substitution of a stop codon for a codon that actually codes for an amino acid - stopping the translation of a protein, almost always leads to the loss of function

Question 36

deletion

Answer 36

- deleltions of 1 or 2 nucelotides are frameshift mutations | - larger scale deletions are chromosomal level

Question 37

duplication

Answer 37

- when large copies of a chromosome are copied - may or may not affect the phenotype of the individual - being put in the middle could have disastrous affects

Question 38

turner's syndrome

Answer 38

- only survivable monosomy - where an individual has an X chromosome without a pair - have more health consequences but can live normal lives