U2T6 - Keywords Flashcards

Population Genetics

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1
Q

Population

A

All of the organisms of one species, who live in the same place at the same time, and can breed together.

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2
Q

Gene Pool

A

Sum total of all genes + alleles in pop/species at particular time. Can vary from generation to generation due to variation + mutations.

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3
Q

Hardy Weinberg Principle/Equation

A

Frequency of dominant + recessive alleles in population remains constant from gen to gen, provided certain conditions exist.

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4
Q

Hardy-Weinberg Formula (A)

A

Allele Frequencies
p + q = 1
p = Frequency of dominant alleles
q = Frequency of recessive alleles

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5
Q

Hardy-Weinberg Formula (B)

A
Genotype Frequencies
p2 + 2pq + q2 = 1
p2 = Frequency of homozygous dominant
2pq = Frequency of heterozygous
q2 = Frequency of homozygous recessive
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6
Q

Allele Frequency

A

Proportion of particular allele in pop/species at particular time.

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7
Q

Genotype Frequency

A

Total num each genotype in given pop

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8
Q

Random Mating

A

Not choosing a mate, like plants. Animals don’t do this.

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9
Q

Shuffle Variation

A

Sources of variation that shuffle existing genetic info, don’t form new forms of alleles/genes. Mutation required for that.

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10
Q

Mutation

A

Permanent, spontaneous changes to the genetic makeup of alleles/num of chromosomes/DNA.

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11
Q

Gene Mutations

A

Occur when there are changes to letters making up triplet code. May be 1 base substitution or deletion or addition of new base. Changes can occur at base pair of DNA of gene. May be caused by chemical/radiation (x-ray). Restricted to 1 gene.

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12
Q

Gene Mutation Substitutions (Sickle Cell Anaemia)

A

Gene for B-Haemoglobin on chromosome 11 prone to single gene mutation + protein synthesis error. Thymine substituted by adenine so CTT becomes CAT. Causes Valine to replace Glutamate so abnormal haemoglobin forms into long fibres that distort RBCs into sickle shapes.

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13
Q

Gene Mutation Deletions

A

Occurs when 1+ nucleotides not copies during DNA replication. Can result in non functional proteins as it shifts ribosome’s reading frame. AA’s coded for after deletion may be totally different to OG DNA molecule.

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14
Q

Chromosome Mutations

A

Occur when large bits/entire/sets of chromosomes fail to segregates. E.g. Down’s Syndrome.

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15
Q

Down’s Syndrome

A

Chromosome 21 doesn’t segregate during meiosis. Egg cell contains 2 copies of chromosome 21 so upon fertilisation, zygote contains 3 copies of chromosome 21, leading is trisomy 21.

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16
Q

Trisomy 21

A

Three copies of chromosome 21 in a zygote.

17
Q

Selection

A

Editing of genetically inheritable features in pop, increases frequency of some while decreasing frequency of others.

18
Q

Natural Selection

A

Presence of variation in pop allows diff members to be more suited to current environmental conditions than others (obtain + use resources, mate, evade predators, catch prey). Impact survival. Most able to survive = fittest. Over time, adaptations of fitter controlled by alleles, favoured + so increase in the allele frequencies so more of the favourable phenotype.Better adapted organisms more likely to survive + produce more offspring. Brings about evolution.

19
Q

Directional Selection

A

Selection of organisms whose phenotype, at 1 end of variation range gives selective advantage. In normal distribution curve, phenotype shifts to left or right (moves moda, value). Most likely when environment changes or pop colonises new habitat. New code = new optimism value.

20
Q

Mode

A

Most common number/phenotype.

21
Q

Stabilising Selection

A

Form of selection that selects against both extremes + favours individuals with average phenotypes. If extremes found, they’re selected against. Common in stable ecosystems. No obvious phenotype change, doesn’t drive evolutionary change. E.g. birth mass in humans (high + low birth weights less likely to survive)

22
Q

Polymorphism

A

Diff forms of organism’s traits that can be found (blood groups, eye colour). Can investigate forms of selection (sickle cell in Central Africa as results in malarial parasite less able to complete life cycle so confers malarial resistance)

23
Q

Species

A

Group of individuals of common ancestry that closely resemble each other + normally capable of interbreeding to produce fertile offspring.

24
Q

Speciation

A

Formation of new species from existing species that are reproductively isolated from other species.

25
Q

Evolution

A

Formation of new species from existing species.

26
Q

Aneuploidy

A

Having abnormal num of chromosomes in haploid set.

27
Q

Polyploidy

A

Having 2+ paired (homologous) sets of chromosomes.

28
Q

Polymorphic Population

A

Occurrence of 2+ diff forms/phenotypes in pop of species.

29
Q

Sympatric Speciation

A

Speciation that occurs when 2 groups of same species live in same place, but evolve differently until they can’t interbreed + are diff species.

30
Q

Interspecific Competition

A

Competition between diff pops for resources.

31
Q

Selection Pressure

A

Agent of diff mortality/fertility that tends to make pop change genetically.

32
Q

Niche

A

Role taken by type of organism within community.

33
Q

Hybridisation

A

Process of animal/plant breeding with individual of another species/variety.

34
Q

Habitat Isolation

A

Populations inhabit different local habitats within one environment.

35
Q

Temporal Isolation

A

Pops use same environment but are reproductively active at diff times.

36
Q

Genome

A

All DNA in individual.

37
Q

Point Mutations

A

Genetic Mutations which affect only 1 base. Can involve substitution/deletion of single bases. Relatively common.

38
Q

Frameshift Mutations

A

When 1 base removed from DNA sequence. Changes entire section of DNA. All amino acids after mutation point may be changed or shortened if stop codon produced earlier than intended.

39
Q

Sub-Species

A

Separate populations that haven’t diverged enough to produce separate species but may in future. Differ in several signif aspects but can still interbreed + produce fertile young.