Genetics and Evolution - created from Mind Map

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Mendelian Inheritance

Law of Segregation:

Law of Independent Assortment

Homozygous

Heterozygous

Monohybrid Cross

Dihybrid Cross

alleles segregate independently when forming gametes

segregation of one pair of alleles is independent to that of another

2 identical alleles

one dominant and one recessive allele

3:1 Phenotype Ratio

1:2:1 Genotype ratio

9:3:3:1 Phenotype Ratio

16 different genotypes

Pedigree Analysis

Autosomal Dominant

Autosomal Recessive

X Linked Dominant

X Linked Recessive

Mitochondrial Inheritance

not sex linked

affected parent = affected individual

need 2 alleles to inherit disease

not sex linked

dominant gene carried on X chromosome

both sexes affected equally

recessive X gene on X chromosome

only 1 sex affected

Inherited via mum

all offspring is affected

Gene Interactions

Complete Dominance

Incomplete Dominance

Co-Dominance

Epistasis

Variable Penetrance

Variable Expressitivity

classic Mendelian inheritance

Heterozygote phenotype is intermediate

both homozygotes displayed

can produce 9 different ratios

no. of individuals carrying particular allele

the extent to which a genotype expresses it's phenotype

Linkage and Recombination

Incomplete Linkage

closer together = more likely to be linked

Linkage- Recom. freq

Independent Assortment, = 50% recomb freq

60% parental, 40% recombination

further apart = more likely to have double crossovers which can undo first crossover

Complex Genetic Traits

Continuous Variation

Discontinuous Variation

Variance

Heritability

Meristic Traits

Threshold Traits

variation from one extreme to another

phenotype is one thing or another

Vp = Vg + Ve

Additive

Dominance

Environmental

Vg = Va + Vd

each allele contributes to phenotype additivetly

either allele can show dominance

Environment has effect on variance along with genetics

Narrow

Broad

h2 = Va / Vp

H2 = Vg / Vp

polygenic and environ. determination

phenotype expressed as a whole number

polygenic and environ. determination

2 states- affected or unaffected

Genetic Mapping

DNA Polymorphisms

RFLPs

SNPs

VNTRs/STRs

Genetic Structure of Populations

Population Genetics

Subpopulation

Gene Pool

Genotype Freq.

Allele Freq.

Hardy-Weinberg Principle

applies genetic principles to entire populations of organisms

population unit, a.k.a local population

all alleles in a population

proportion of indiv. in population wtih specific genotype

proportion of each indiv. allele in a population

p2 + 2pq + q1 =1

Inbreeding

combine alleles of common ancestry

Leads to genes becoming fixed and loss of variation

Commercial use in plants

Heterosis

rapid growth, larger size, bigger crop yield

Forces of Evolutionary Change

Mutastion

Modes of Natural Selection

ultimate source of variation

caused by UV and chemicals

Stabilizing Selection

Directional Selection

Diversifying Selection

Balancing Selection

Migration

Genetic Drift

intermediate favoured over extreme phenotypes

change in environ. drives selection towards certain phenotype

creates 2 peaks- 2 outlying phenotypes preferred

Heterozygote advantage

movement of alleles between population

can fix genes in population after interbreeding

Selection

Evolution

Individual Fitness

Genotype Fitness

Relative Fitness

Drivers of Natural Selection

Sexual Selection

process of change in inherited characters of a population over successive generations

ability to survive and reproduce

mean fitness of all people in the population with genotype

standardised measure relative to fittest genotype

made up of survival and reproductive components

changing environment

random mutation

selection that favours traits that increase reproductive success

Intra Sexual

Inter Sexual

competition for mates

mate choice

Speciation and Species

Micro-evolution

Macro-evolution

Speciation

Mating Mechanisms

Species

evolution within population/species

evolution within taxa

2 species formed from one and cannot reproduce any more

Allopatric

Peripatric

physical isolation

geographical isolation

Pre

Post

ecological, seasonal, sexual, mechanical

gametic isolation, hybrid viability, hybrid sterility, hybrid breakdown

Sibling

Sub

2 species similar in morphology

distinguishable by more than one character

Phylogeny

Cladogenesis

Anagenesis

Terminology

splitting of evolutionary lineages to form clades

Monophyletic

Paraphyletic

Polyphyletic

all related

ancestor and some descendants related

2 convergent descendants but no common ancestor

change within species over time

Plesiomorphy

Apomorphy

Symplesiomorphy

Synapomorphy

character state found in ancestor of group

derived character state in descendants

shared ancestral character state

shared derived character state

Altruism

An action which increases fitness of another whilst reducing fitness of actor

Mechanisms

Hamilton's Rule

Group Selection

Kin Selection

Reciprocal Altruism

Status

rb-c > 0

Biodiversity and Conervation

Levels

Species-Area Relationship

Threats to biodiversity

Genetic

Organism

Ecosystem

lower latitude = more diverse

larger areas = more species

Human activity = biggest threat

6th mass extinctions?

Genetics and Evolution