Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Genes Evo & Dev Y1 > Genes L8 > Flashcards

Genes L8 Flashcards

1
Q

What is microevolution?

A
  • Changes -> gene pool -> organism -> overtime
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a gene pool?

A
  • All alleles of all genes -> all individuals -> population.
  • Represents genetic variation -> population
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are alleles?

A
  • Different forms/types of gene -> polymorphisms.

Mutation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the term polymorphic used to describe?

A
  • Gene locus with more than one allele
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is macroevolution?

A 
•	Macroevolution:
-	Large scale evolution
-	Evolution across major animal groups
	Above species level 
Eg. Phyla, Order, Phyla etc. 
-	Speciation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Contrast microevolution & macroevolution.

A 
•	Macroevolution:
-	Large scale evolution
-	Evolution across major animal groups
	Above species level 
Eg. Phyla, Order, Phyla etc. 
-	Speciation

• Microevolution:

  • Evolution within species or population
  • Microevolution & Chance -> macroevolution.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What results in macroevolution occurring?

A
  • Microevolution & Chance -> macroevolution.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Requirements for evolution by natural selection?

A
  • Varying reproductive successes

- Genetic variation -> (Differences between individuals)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is evolution?

A

• Evolution -> changes -> genetic structure -> population/species -> over time.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe what population genetics is.

A

• Population genetics
- Study of genetic changes -> evolution.
- Study of microevolution
>Darwin’s theory -> evolution by natural selection
> Mendel’s theory -> inheritance
- Modern synthesis / neo-Darwinism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What can population genetics be used to investigate in terms of human pathogens?

A

Evolving human pathogens

Human evolution in response to pathogens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Use of population genetics in investigating evolving human pathogens?

A 
	Evolving human pathogens:
-	Bacteria 
-> Antibiotic resistance Eg. MRSA
-	Viruses
-> Anti-viral drug resistance Eg. HIV
-	Emerging pathogens
Eg. Ebola, influenza viruses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Use of population genetics in investigating human evolution in retaliation to pathogens?

A

 Human evolution -> pathogens:

  • Resistance
  • > blood-bourne parasites Eg. Malaria parasites, Plamodium sp.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Use of population genetics in wild populations?

A

• Uses of population genetics in wild populations:

  • Range/quantity & distribution -> genetic diversity
  • Response -> population -> change
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe the gene locus model & what is is used for.

A 
•	Single gene locus model 
-	Used to study gene pool
-	Diploid organisms
>Single gene
>> 2 alternative alleles
i)	R -> dominant
ii)	r -> recessive
-	3 genotypes
	RR -> Homozygous
	Rr -> Heterozygous
	rr -> Homozygous 
>> 2 phenotypes
RR & Rr -> red flower
rr -> white flowers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is a genotype?

A

• Genotype:

- The genetic composition of an organism determining a particular characteristic (phenotype).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is a phenotype?

A

• Phenotype:

- Observable characteristics of an organism as a result of interaction between it’s genotype & their environment.

18
Q

What is measured in the gene pool? Describe how both of these are calculated.

A
  • Allele/Allelic frequency:
    (Number of particular type of allele)/(Total number of alleles)
  • Genotype/Genotypic frequency:
    (Number of individuals with one particular genotype)/(Total number of all individuals)
19
Q

Describe the Hardy-Weinburg equilibrium.

A 
•	Hardy-Weinburg equilibrium:
-	Allele & genotype frequencies reach an equilibrium over time & remain unchanged. 
-	p2 + 2pq +q2 = 1
Genotype frequency: f(RR) + f(Rr) + f(rr) =1
Allele frequencies -> p & q
  >> p + q = 1
	Conditions:
Large population size
Random reproduction
No migration of populations
No selection
No mutation
20
Q

Equation of genotypic frequency for H-W eqm?

A
  • p2 + 2pq +q2 = 1

Genotype frequency: f(RR) + f(Rr) + f(rr) =1

21
Q

Equation of allelic frequency for H-W eqm?

A

Allele frequencies -> p & q

|&raquo_space; p + q = 1

22
Q

What is the definition of the H-W principle and what are it’s conditions?

A 
-	Allele & genotype frequencies reach an equilibrium over time & remain unchanged. 
	Conditions:
Large population size
Random reproduction
No migration of populations
No selection
No mutation
23
Q

Calculate the allelic frequency for both allele types from a population of 100 in which 40-> homozygous dominant
50-> heterozygous & 10-> homozygous recessive.

A
  • F(A1A1) = 40/100 = 0.4
  • F(A1A2) = 50/100 = 0.5
  • F(A2A2) = 10/100 = 0.1
  • Allele frequency A1 = (No. of A1 alleles)/(Total no. of alleles)
    [2(40) + 50]/200 = 130/200 = 0.65

 Allele frequency: If 100 genotypes – 2 alleles per genotype -> 200.
Dominant alleles -> Homozygous dominant -> A1A1
-> 2 dominant alleles per homozygous dominant genotype
Heterozygous -> A1A2 -> 1 dominant allele per heterozygous.
Homozygous recessive -> A2A2 -> No dominant alleles per genotype
» No. of alleles = 2(No. of homozygous dominant genotype) + 1(No. heterozygous genotype)

  • Allele frequency A2 = (No. of A2 alleles)/(Total no. of alleles)
    [50 + 2(10)]/200 = 70/200 = 0.35.
    Recessive alleles -> homozygous recessive -> A2A2
    ->2 recessive alleles per homozygous recessive genotype
    Heterozygous -> A1A2 => 1 recessive allele per heterozygous genotype
    Homozygous dominant -> A1A1 -> No dominant alleles per genotype
    &raquo_space; No. of recessive alleles = 2(No. of homozygous recessive genotype) +
    1(No. of heterozygous genotype)
24
Q

• If 70% of population of has dominant (R) allele, calculate the genotype frequencies of the population.

A 
	p+q=1
p=0.7 -> q=1-0.7 -> 0.3 
	Genotype frequencies: f(RR) + f(Rr) + f(rr) = 1
p2= (0.7)2 -> q2= (0.3)2
(0.7)2 + 2pq + (0.3)2 = 1
    2pq = 1 -0.58 -> 0.42
       pq= 0.42/2 -> 0.21
	p2 = homozygous dominant (RR)
>	(0.7)2 ->0.45 
	q2 = homozygous recessive (rr)
>	(0.3)2 -> 0.09 
	2pq = heterozygous (Rr)
>	2(0.7)(0.3) = 0.42
25
Q

What test do you use to find if observed & expected values of H-W test are significant?

A

Chi-squared

26
Q

• All patients with cystic fibrosis have a recessive mutation -> homozygous for allele. 1/2500 are affected. Assuming population at H-W eqm, what is the expected frequency of individuals who are heterozygous for the disease causing allele?

A
  • q = sqrt(0.0004) -> 0.02
  • p = 1-0.02 -> 0.98
  • p2 + 2pq + q2 = 1
  • 2pq -> 2(0.98)(0.02) -> 0.0392
27
Q

Name the factors affecting allele & genotype frequencies.

A

Genetic drift
Non-random reproduction
Migration
Selection

28
Q

Describe how genetic drift can affect allele & genotype frequencies.

A
  • Genetic drift -> low population
    Change -> allele frequencies -> chance events
    i) Founder effect:
    Small no. of individuals -> start new population
    ii) Bottleneck:
    No. of breeding individuals -> reduced -> chance event
29
Q

Describe how non-random reproduction can affect allele & genotype frequencies.

A 
Sexual selection
Assortative mating 
i)	Positive
Mate -> unrelated partners -> similar phenotype
>>Decreases heterozygosity 
>>Increases homozygosity 
Eg. Inbreeding 
Inbreeding depression:
Reduced fitness -> expression of harmful, recessive alleles. 
ii)	Negative 
Mate -> unrelated partners -> different phenotype 
>>Increases heterozygosity 
>>Decreases homozygosity
30
Q

Describe how Selection can affect allele & genotype frequencies.

A 
Natural selection
Acts on phenotyoes -> gene pool 
i)	Stabilising 
ii)	Directional 
iii)	Disruptive
31
Q

Describe how - Migration/Gene flow can affect allele & genotype frequencies.

A

Transfer of alleles -> between diff populations
&raquo_space;If gene flow prevented -> speciation possible
&raquo_space;Helps maintain genetic variation

32
Q

What is a factor required for natural selection?

A

• Natural selection requires heritable genetic variation.

33
Q

Name the methods in which genetic variation can be preserved.

A

Balancing selection
Clinical variation
Diploidy
Neutral alleles

34
Q

Describe how balancing selection can preserve genetic variation.

A

 Balancing selection
» Heterozygote advantage
Higher fitness than either homozygote
Eg. Sickle-cell anemia
»Frequency dependent selection
Allele selected against -> high frequency
Allele selected for -> low frequency
Eg. Scale-eating fish
»Left & right mouthed predators
Left -> attack back right flank
Right -> attack back left flank
-»If high no. right mouthed
– Prey expecting to be attacked -> left flank
– Less likely to predict attack -> right flank
– Left mouthed have advantage -> incr. no. of left-mouthed individuals.
-»Low no. right mouthed
–High no left mouthed -> expect attack on right flank
– Incr. success of right mouthed -> pop. Incr.

35
Q

Describe how clinical variation can preserve genetic variation.

A

 Clinal variation

|&raquo_space;Different selective pressures -> across geographic range -> population

36
Q

Describe how diploidy can preserve genetic variation.

A

 Diploidy:
 If deleterious (harmful) allele recessive -> selection can only act on homozygous recessive genotype
»Remaining deleterious alleles -> hidden -> heterozygotes -> not expressed.

37
Q

Describe how neutral alleles can preserve genetic variation.

A

 Neutral alleles:
Nucleotide differences -> don’t effect fitness of organisms
>Synonymous mutations
&raquo_space;Don’t alter amino acid seq.
>Non-synonymous mutations
&raquo_space;Alter amino acids seq.
Most nucleotide differences -> sections of genome -> don’t encode proteins.

38
Q

What is the sexual selection theory?

A

• Sexual selection theory:

- Males would want to mate with the max. number of possible females

39
Q

What is the sexual conflict theory?

A

• Sexual conflict theory:

- Sexual selection theory of males conflicts with females desire to mate with fittest males only.

40
Q

What is polyandry?

A

• Polyandry:

- Female has more than one male mate.

41
Q

What is polygyny?

A

• Polygyny:

- Male has more than one female mate.

42
Q

Give an example of a case study demonstrating how population genetics can be used.

A

• Population genetics case study: Cheetahs
- 1900: >100,000 -> 2014: ~10,000.
- 2 population bottlenecks:
 100,000 yrs -> migration -> N. America – Africa
 11-13,000 yrs -> Pleistocene mammal extinction
- Poor sperm quality, low fecundity & high susceptibility to infection.
- Solitary females -> large range: >800km2
- Male coalitions (2-3 brothers) -> small territories: 40km2
- Solitary males (floaters) -> large range
- Males only associate -> females -> mating
No parental care
- DNA samples -> paternity testing
43% litters -> fathered by more than one male
>Often outside females range
 Example of polyandry

Genes Evo & Dev Y1 (23 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions