Evolutionary Mechanisms?!?!?!?!?!?!?!?

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Evolutionary Mechanisms?!?!?!?!?!?!?!?

!WOOO Things Change!WOOO Things Change!

Fundamental Concept of Syngameon (whatever that

means)

Fundamental Concept of Syngameon (whatever that

means) Genes are carried from one

generation to the next through reproduction and they construct proteins through the processes of Transcription and Translation

A Gene pool is the set of all genes in a species or population.

Genes are carried from one generation to the next through reproduction and they construct proteins through the processes of Transcription and Translation

A Gene pool is the set of all genes in a species or population.

There are no Existing Primitive Species (Except

for freshman)

There are no Existing Primitive Species (Except

for freshman) So all eukaryotes derived from a

single primitive, ancestral prokaryote and thus all eukaryotes have evolved for the same amount of time.

Seemingly primitive characteristics are just highly efficient and have not needed to change much over time.

So all eukaryotes derived from a single primitive, ancestral prokaryote and thus all eukaryotes have evolved for the same amount of time.

Seemingly primitive characteristics are just highly efficient and have not needed to change much over time.

Evolution Needs Change All the Time (Isn’t that

Demanding)

Evolution Needs Change All the Time (Isn’t that

Demanding) Variation comes in the forms of genetic

mutation which can be neutral, beneficial, or deleterious.

There are 2 types of Evolutionary mechanisms: Those that increase variation, and those that decrease variation.

Mechanisms that increase variation are mutations, recombination, and gene flow.

Mechanisms that decrease variation are Natural Selection and Genetic drift.

Variation comes in the forms of genetic mutation which can be neutral, beneficial, or deleterious.

There are 2 types of Evolutionary mechanisms: Those that increase variation, and those that decrease variation.

Mechanisms that increase variation are mutations, recombination, and gene flow.

Mechanisms that decrease variation are Natural Selection and Genetic drift.

Increasers of Variation are GOOD!

Increasers of Variation are GOOD!

Mutations occur at either the molecular level or the chromosomal level.

Chromosomal mutations are Deletions, Duplications, Inversions, Insertions, Translocations, and numerous other abnormalities involving too many chromosomes or too little. (see diagram on page 81)

Molecular mutations are either point mutations, when one nucleotide is switched with another, or frame shifts, when one nucleotide is either deleted or inserted randomly.

Mutations occur at either the molecular level or the chromosomal level.

Chromosomal mutations are Deletions, Duplications, Inversions, Insertions, Translocations, and numerous other abnormalities involving too many chromosomes or too little. (see diagram on page 81)

Molecular mutations are either point mutations, when one nucleotide is switched with another, or frame shifts, when one nucleotide is either deleted or inserted randomly.

Types of Point Mutations (sorry for boring title)

Types of Point Mutations (sorry for boring title)

Point mutations can be nonsense mutations and this is when the mutations stops the production of a protein before it is supposed to be stopped thus making it a useless protein or giving it a different use.

They can also be mis-sense mutations which change one amino acid in the protein chain sometimes changing its shape and its function. These may also result in silent mutations that have no effect (they are boring like my title)

Point mutations can be nonsense mutations and this is when the mutations stops the production of a protein before it is supposed to be stopped thus making it a useless protein or giving it a different use.

They can also be mis-sense mutations which change one amino acid in the protein chain sometimes changing its shape and its function. These may also result in silent mutations that have no effect (they are boring like my title)

Recombination= ….. Exactly what it sounds like

Recombination= ….. Exactly what it sounds like This involves the re-assortment of genes

through Crossing Over, the exchange of genetic material between homologous chromosomes, this happens during meiosis!!!!

Linkage disequilibrium is the distance between two genes on the same chromosome. If the genes are adjacent to each other on the chromosome then they will be transmitted together more frequently than they should be.

This involves the re-assortment of genes through Crossing Over, the exchange of genetic material between homologous chromosomes, this happens during meiosis!!!!

Linkage disequilibrium is the distance between two genes on the same chromosome. If the genes are adjacent to each other on the chromosome then they will be transmitted together more frequently than they should be.

Gene Flow, also what it sounds like but it is cooler

than Recombination

Gene Flow, also what it sounds like but it is cooler

than Recombination This happens when genes flow from one

population to another through organisms that randomly want to migrate and then mate with the locals giving them new versions of the same genes, alleles.

This does not usually decrease the genes of the old gene pool since the organisms in that population have randomly mated for multiple generations so the alleles would probably already be distributed throughout the old population by the time and organism wishes to leave.

This happens when genes flow from one population to another through organisms that randomly want to migrate and then mate with the locals giving them new versions of the same genes, alleles.

This does not usually decrease the genes of the old gene pool since the organisms in that population have randomly mated for multiple generations so the alleles would probably already be distributed throughout the old population by the time and organism wishes to leave.

Genetic drift: The Murderer of unexpressed Alleles through

Chance

Genetic drift: The Murderer of unexpressed Alleles through

Chance This results in the change of relative

proportions of different alleles that come from the random sampling associated with sexual reproduction. In other words it’s chance that an allele is passed because it is chance that a certain allele ends up in the sperm that gets to the egg first or that that allele even is in the egg in the first place.

This results in the change of relative proportions of different alleles that come from the random sampling associated with sexual reproduction. In other words it’s chance that an allele is passed because it is chance that a certain allele ends up in the sperm that gets to the egg first or that that allele even is in the egg in the first place.

Natural Selection……… AGAIN.

Natural Selection……… AGAIN.

Based on the viability of different genotypes that appear as phenotypic differences that affect the ability to attract a mate and continue on the species

There are 3 basic types of Natural Selection: 1) Directional Selection 2) Stabilizing Selection 3) Disruptive Selection

Based on the viability of different genotypes that appear as phenotypic differences that affect the ability to attract a mate and continue on the species

There are 3 basic types of Natural Selection: 1) Directional Selection 2) Stabilizing Selection 3) Disruptive Selection

The Crazy Types of Selection

The Crazy Types of Selection

Directional selection is when one extreme phenotype is favored.

Stabilizing selection is when an intermediate phenotype is favored

Disruptive selection is when either extreme phenotype is favored and the intermediate phenotype is not.

Directional selection is when one extreme phenotype is favored.

Stabilizing selection is when an intermediate phenotype is favored

Disruptive selection is when either extreme phenotype is favored and the intermediate phenotype is not.

Natural Selection is not Psychic

Natural Selection is not Psychic

Rapidly changing environmental conditions can impose new challenges that may result in the species extinction

Also mechanisms of evolution do not always favor the fittest in the population but many that are tolerably fit.

Rapidly changing environmental conditions can impose new challenges that may result in the species extinction

Also mechanisms of evolution do not always favor the fittest in the population but many that are tolerably fit.

More About What Evolution is

More About What Evolution is

Evolutions is a change in the gene pool of a population over a period of time.

Cool Example: the English moth Biston betularia has two main colorations, Light and Dark. Dark moths consisted of less than 2% of a population before 1848, by 1898 95% moths in urban areas in Britain were dark moths. This is because the environment around the moths changed because of the industrial revolution and this made everything all dark and sooty, thus the dark moths could blend in better.

Evolutions is a change in the gene pool of a population over a period of time.

Cool Example: the English moth Biston betularia has two main colorations, Light and Dark. Dark moths consisted of less than 2% of a population before 1848, by 1898 95% moths in urban areas in Britain were dark moths. This is because the environment around the moths changed because of the industrial revolution and this made everything all dark and sooty, thus the dark moths could blend in better.

What? I Can’t Sprout Wings Because I Want To?

What? I Can’t Sprout Wings Because I Want To? POPUATIONS EVOLVE NOT

INDIVIDUALS!!!!!!!!!!!! When populations evolve the

genotypic ratios are changing.

POPUATIONS EVOLVE NOT INDIVIDUALS!!!!!!!!!!!!

When populations evolve the genotypic ratios are changing.

Two Types of Evolution?Two Types of Evolution?

They say that but it’s not really true. Microevolution is when one species changes

to better suit its surroundings, so the Moth example we just talked about.

Macroevolution is when a new species is created so really this is just a lot of microevolution. Thus they’re really the same thing the packet just wants to confuse you.

Another thing: Abiogenesis is the theory of how life first formed and this is usually called evolution so don’t mix them up.

They say that but it’s not really true. Microevolution is when one species changes

to better suit its surroundings, so the Moth example we just talked about.

Macroevolution is when a new species is created so really this is just a lot of microevolution. Thus they’re really the same thing the packet just wants to confuse you.

Another thing: Abiogenesis is the theory of how life first formed and this is usually called evolution so don’t mix them up.

Things that people confuse about Evolution (this isn’t

confusing at all)

Things that people confuse about Evolution (this isn’t

confusing at all) Morphological change can occur with out

Evolution and vice versa. Evolution is not progress, meaning

organisms do not necessarily become better over time.

Example: Paquin and Adams performed an experiment with yeast and compared the different types to each other and sometimes the old types over took the new types.

Morphological change can occur with out Evolution and vice versa.

Evolution is not progress, meaning organisms do not necessarily become better over time.

Example: Paquin and Adams performed an experiment with yeast and compared the different types to each other and sometimes the old types over took the new types.

More Confusion Happening and Doing Stuff

More Confusion Happening and Doing Stuff

Organisms are NOT passive targets for their environment meaning that each species modifies the environment around them to best suit their needs too.

Organisms are NOT passive targets for their environment meaning that each species modifies the environment around them to best suit their needs too.

Genetic Variation Is Needed for Everything!

Genetic Variation Is Needed for Everything!

Evolution needs genetic variation, in the moth example, if there were no dark moths then all the moths would have died.

Mutations provide variation by changing genes and then Natural Selection decides if the change will be allowed to stay.

Evolution needs genetic variation, in the moth example, if there were no dark moths then all the moths would have died.

Mutations provide variation by changing genes and then Natural Selection decides if the change will be allowed to stay.

Two Ways to Diversify Genetic Variation

Two Ways to Diversify Genetic Variation

Allelic diversity or non-random association of alleles.

Allelic diversity is exactly what it sounds like and this works because most animals are Diploid meaning they have two alleles for each locus, one from mom and one from dad.

If you have two of the same alleles then you are Homozygous, if you have two different alleles you are Heterozygous.

Allelic diversity or non-random association of alleles.

Allelic diversity is exactly what it sounds like and this works because most animals are Diploid meaning they have two alleles for each locus, one from mom and one from dad.

If you have two of the same alleles then you are Homozygous, if you have two different alleles you are Heterozygous.

Examples of Allelic Diversity that have Numbers in Them

Examples of Allelic Diversity that have Numbers in Them

Lots of variation is in natural populations, at 45% of plant loci there are more than one allele in the gene pool. Birds have more than one allele at 15% of their loci, insects at 50%, mammals and reptiles at 20%, and amphibians and fish at 30%.

Lots of variation is in natural populations, at 45% of plant loci there are more than one allele in the gene pool. Birds have more than one allele at 15% of their loci, insects at 50%, mammals and reptiles at 20%, and amphibians and fish at 30%.

Linkage Disequilibrium (or Linked Genes)

Linkage Disequilibrium (or Linked Genes)

This measures the association between the alleles two different genes. If two alleles are found together in an organism more often than expected, then the alleles are linked.

There is an equation that is important so highlight it and it tells us the linkage between to alleles. The range for this is between 1/4 and -1/4, the greater away from 0 the more the alleles are linked.

This can be because of the alleles being on the same gene or because the two alleles work together to keep the organism alive.

This measures the association between the alleles two different genes. If two alleles are found together in an organism more often than expected, then the alleles are linked.

There is an equation that is important so highlight it and it tells us the linkage between to alleles. The range for this is between 1/4 and -1/4, the greater away from 0 the more the alleles are linked.

This can be because of the alleles being on the same gene or because the two alleles work together to keep the organism alive.

Natural Selection and Linkage DisequilibriumNatural Selection and Linkage Disequilibrium

An example of Natural selection keeping alleles linked is in the moth Papilio memnon

There are alleles in this moth that code for wings with a tail and wings without a tail, there are another set of alleles for bright wings and dark wings.

Only bright, tailed moths and dark, non-tailed moths are found in the wild even though a dark, tailed and a bright, non-tailed can be produced from a cross of these two phenotypes.

This is because bright, tailed moths mimic another species that is poisonous, and the dark non-tailed get camouflaged.

An example of Natural selection keeping alleles linked is in the moth Papilio memnon

There are alleles in this moth that code for wings with a tail and wings without a tail, there are another set of alleles for bright wings and dark wings.

Only bright, tailed moths and dark, non-tailed moths are found in the wild even though a dark, tailed and a bright, non-tailed can be produced from a cross of these two phenotypes.

This is because bright, tailed moths mimic another species that is poisonous, and the dark non-tailed get camouflaged.

Hardy Weinberg And Assortative Mating

Hardy Weinberg And Assortative Mating

Hardy-Weinberg equilibrium is the distribution of which alleles will be found in a population based on their frequency.

Non-random Mating results from not going with the Hardy Weinberg Equilibrium and choosing which organism you wish to mate with.

Hardy-Weinberg equilibrium is the distribution of which alleles will be found in a population based on their frequency.

Non-random Mating results from not going with the Hardy Weinberg Equilibrium and choosing which organism you wish to mate with.

More About Natural Selection For like the 80th

Time!!!!!!

More About Natural Selection For like the 80th

Time!!!!!! Natural Selection is the ONLY mechanism of adaptive evolution.

It usually acts to get rid of unfit variants produced through mutation, it kills new alleles before they can go through the population. This made George Williams say “Evolution proceeds in spite of Natural Selection”

Natural Selection can either maintain or deplete genetic variation. When it causes the deletion of one allele, or the fixation of another, it depletes variation.

When heterozygotes are more fit than either homozygous pair then Natural Selection maintains genetic variation, this is called Balancing Selection and it’s really rare.

Natural Selection is the ONLY mechanism of adaptive evolution.

It usually acts to get rid of unfit variants produced through mutation, it kills new alleles before they can go through the population. This made George Williams say “Evolution proceeds in spite of Natural Selection”

Natural Selection can either maintain or deplete genetic variation. When it causes the deletion of one allele, or the fixation of another, it depletes variation.

When heterozygotes are more fit than either homozygous pair then Natural Selection maintains genetic variation, this is called Balancing Selection and it’s really rare.

Cool Example that Involves Deadly Diseases

Cool Example that Involves Deadly Diseases

The maintenance of sickle cell anemia in populations plagued by malaria.

If you have two alleles for sickle cell anemia, you are anemic and you die.

If you have two alleles for regular red blood cell shape, you catch malaria and you die.

If you have one of each, oxygen is still able to go through your blood because of normal red blood cells and the shape of the sickle cell blood cells makes it hard for plasmodia to enter the cell.

The maintenance of sickle cell anemia in populations plagued by malaria.

If you have two alleles for sickle cell anemia, you are anemic and you die.

If you have two alleles for regular red blood cell shape, you catch malaria and you die.

If you have one of each, oxygen is still able to go through your blood because of normal red blood cells and the shape of the sickle cell blood cells makes it hard for plasmodia to enter the cell.

Units of Natural Selection???

Units of Natural Selection???

Individuals that either reproduce or don’t reproduce and that is a unit of natural selection.

Genes and groups of organisms are NOT units of natural selection

Individuals that either reproduce or don’t reproduce and that is a unit of natural selection.

Genes and groups of organisms are NOT units of natural selection

Organisms are Always Selfish!

Organisms are Always Selfish!

An individual does not do anything to help its own species since that is who they are competing against.

Reciprocal altruism is cooperating with other organisms.

An example is blood sharing in vampire bats. Those who find a meal usually regurgitate some blood so that an unsuccessful bat that they have partnered with can have a meal. If a partner only takes and never gives then the other bat will leave the cheater.

So organisms only perform acts that are mutually beneficial.

Also selfish in evolutionary talk means that ones own inclusive fitness is maximized, and altruistic means that another’s fitness is increased by expense of their own.

An individual does not do anything to help its own species since that is who they are competing against.

Reciprocal altruism is cooperating with other organisms.

An example is blood sharing in vampire bats. Those who find a meal usually regurgitate some blood so that an unsuccessful bat that they have partnered with can have a meal. If a partner only takes and never gives then the other bat will leave the cheater.

So organisms only perform acts that are mutually beneficial.

Also selfish in evolutionary talk means that ones own inclusive fitness is maximized, and altruistic means that another’s fitness is increased by expense of their own.

Direct, Indirect, and Inclusive Fitness

Direct, Indirect, and Inclusive Fitness

Direct fitness is a measure of how many alleles on average a genotype contributes to the gene pool.

Indirect fitness is a measure of how many alleles identical to its own an organism helps to contribute to the gene pool.

Inclusive fitness is the combination of these types of fitness.

J.B.S. Haldane said he would gladly drown if he could save 2 siblings or 8 cousins.

Direct fitness is a measure of how many alleles on average a genotype contributes to the gene pool.

Indirect fitness is a measure of how many alleles identical to its own an organism helps to contribute to the gene pool.

Inclusive fitness is the combination of these types of fitness.

J.B.S. Haldane said he would gladly drown if he could save 2 siblings or 8 cousins.

How Organisms Sometimes Rely ONLY on

Indirect Fitness

How Organisms Sometimes Rely ONLY on

Indirect Fitness In diploid species siblings share 50% of each other’s genes. It is more if the parents are related.

Sometimes organisms will not reproduce at all but instead help their relatives reproduce because their indirect fitness is higher than their direct fitness.

Insects do this a lot, there are sterile castes of insects that specifically help their queen to reproduce so that there will be a greater number of their own alleles in the next generation.

In diploid species siblings share 50% of each other’s genes. It is more if the parents are related.

Sometimes organisms will not reproduce at all but instead help their relatives reproduce because their indirect fitness is higher than their direct fitness.

Insects do this a lot, there are sterile castes of insects that specifically help their queen to reproduce so that there will be a greater number of their own alleles in the next generation.

Selection Only Works with What is in the PopulationSelection Only Works with What is in the Population

This means that Natural Selection can only distinguish between existing variants and that variants can’t be anything imaginable.

Example: you can’t have a steel shelled turtle. IT IS IMPOSSIBLE FOR NATURAL SELECTION TO MAKE ONE. This is because there is no allele for a steel shelled turtle.

This means that Natural Selection can only distinguish between existing variants and that variants can’t be anything imaginable.

Example: you can’t have a steel shelled turtle. IT IS IMPOSSIBLE FOR NATURAL SELECTION TO MAKE ONE. This is because there is no allele for a steel shelled turtle.

Natural Selection may not lead to the Best Traits

Available

Natural Selection may not lead to the Best Traits

Available In any population there is an optimum set of traits (Global Optimum)

Then there are really good sets of traits (Local Optima)

Sometimes a population can’t go from the local optima to the global optimum because that would mean traversing through less fit states for an organism so organisms stay at the local optima figuring that this is good enough for their species.

This was thought up by Sewall Wright.

In any population there is an optimum set of traits (Global Optimum)

Then there are really good sets of traits (Local Optima)

Sometimes a population can’t go from the local optima to the global optimum because that would mean traversing through less fit states for an organism so organisms stay at the local optima figuring that this is good enough for their species.

This was thought up by Sewall Wright.

Misconceptions On Natural Selection

Misconceptions On Natural Selection

It is not some magical force that pressures organisms into a more adaptive state. Selection just favors beneficial changes that occur by chance.

Most living organisms don’t have conscious motives and Natural selection does not give them this.

“Survival of the fittest” is not natural selection. Survival is only one part of natural selection the other part is actually mating and passing on ones genes.

It is not some magical force that pressures organisms into a more adaptive state. Selection just favors beneficial changes that occur by chance.

Most living organisms don’t have conscious motives and Natural selection does not give them this.

“Survival of the fittest” is not natural selection. Survival is only one part of natural selection the other part is actually mating and passing on ones genes.

Animals Like other Animals that Look Good

Animals Like other Animals that Look Good

Lots of times males acquire secondary sexual characteristics to attract a mate.

Many of these traits are a liability on a survival stand point but they evolve because they attract more mates more often than the organisms are killed.

In some species sexual selection has caused most of the ladies to be monopolized by a few of the males. So males compete to become the ones that monopolize the ladies so that hey can pass on their genes.

This competition also gives the females the choice of the males that they want.

Lots of times males acquire secondary sexual characteristics to attract a mate.

Many of these traits are a liability on a survival stand point but they evolve because they attract more mates more often than the organisms are killed.

In some species sexual selection has caused most of the ladies to be monopolized by a few of the males. So males compete to become the ones that monopolize the ladies so that hey can pass on their genes.

This competition also gives the females the choice of the males that they want.

Animals also like other Animals that won’t get

them Sick

Animals also like other Animals that won’t get

them Sick Another thing that arises from sexual selection

and the bright coloring of males is the health of the male.

The brighter the color the male is, the less infested with parasites he is and so all the girls like him and choose him for their mate.

Another thing that arises from sexual selection and the bright coloring of males is the health of the male.

The brighter the color the male is, the less infested with parasites he is and so all the girls like him and choose him for their mate.

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are needed to see this picture.

QuickTime™ and a decompressor

are needed to see this picture.

R.A. Fisher’s Weird Model for Sexual Selection

R.A. Fisher’s Weird Model for Sexual Selection

It is called the runaway sexual selection model and it proposes that all females have an innate preference for some trait the male will have before it is present in the population.

Females would then mate with the males that carry these traits once they appear and the offspring of this couple would have the traits that attract and the traits that are attracted so the process snowballs and becomes a great big mess until natural selection comes in and makes sure it doesn’t become too out of hand.

It is called the runaway sexual selection model and it proposes that all females have an innate preference for some trait the male will have before it is present in the population.

Females would then mate with the males that carry these traits once they appear and the offspring of this couple would have the traits that attract and the traits that are attracted so the process snowballs and becomes a great big mess until natural selection comes in and makes sure it doesn’t become too out of hand.

Genetic Drift is ConfusingGenetic Drift is Confusing

Genetic drift is the increasing or decreasing of allele frequency from one generation to the next just through chance.

Genetic drift is independent of population size.

Sharp drops in population sizes can change allele frequencies a lot because a lot of alleles are lost from the gene pool when the population drops, this is also a part of genetic drift and it is called the founder effect.

Genetic drift is the increasing or decreasing of allele frequency from one generation to the next just through chance.

Genetic drift is independent of population size.

Sharp drops in population sizes can change allele frequencies a lot because a lot of alleles are lost from the gene pool when the population drops, this is also a part of genetic drift and it is called the founder effect.

Genetic Drift’s ImportanceGenetic Drift’s Importance

Sewall Wright and R.A. Fisher disagree on genetic drift’s importance.

Wright said that populations could be divided into subpopulations and drift could cause great allele frequency differences

Fisher said that populations were large enough to make Genetic drift unimportant.

Sewall Wright and R.A. Fisher disagree on genetic drift’s importance.

Wright said that populations could be divided into subpopulations and drift could cause great allele frequency differences

Fisher said that populations were large enough to make Genetic drift unimportant.

Mutation Once AgainMutation Once Again

Mutations limit the rate of evolution, which can be expressed as the number of nucleotide substitutions in a lineage per generation.

But that is not always so because environments can change and make previously neutral mutations have a selective value.

Mutations limit the rate of evolution, which can be expressed as the number of nucleotide substitutions in a lineage per generation.

But that is not always so because environments can change and make previously neutral mutations have a selective value.

Neutral MutationsNeutral Mutations

These guys come and go and there are multiple equations that calculate the time at which it takes for them to disappear.

Also they occur at the same rate no matter the populations size.

The rate of mutation depends on the heterozygosity (amount of heterozygotes) of the population and there is also an equation for this.

These guys come and go and there are multiple equations that calculate the time at which it takes for them to disappear.

Also they occur at the same rate no matter the populations size.

The rate of mutation depends on the heterozygosity (amount of heterozygotes) of the population and there is also an equation for this.

Ewens-Watterson Distribution

Ewens-Watterson Distribution

When few neutral alleles have medium frequencies and many have low frequencies and all of this happens because of drift.

When few neutral alleles have medium frequencies and many have low frequencies and all of this happens because of drift.

Deleterious Alleles Deleterious Alleles

These usually drop out of the gene pool right away, but if the allele is recessive then it may drift to a higher frequency since natural selection can’t see it. Many disease causing alleles remain in the population this way.

Mutant Load is when deleterious alleles remain in the population at low frequencies due to a balance of recurrent mutation and selection.

These usually drop out of the gene pool right away, but if the allele is recessive then it may drift to a higher frequency since natural selection can’t see it. Many disease causing alleles remain in the population this way.

Mutant Load is when deleterious alleles remain in the population at low frequencies due to a balance of recurrent mutation and selection.

Beneficial Alleles Beneficial Alleles

Wright Calculated the probability of fixation of a beneficial allele as 2s and with that he found that the over all rate of evolution was k=4Nvs this means that an allele with 1% increase in the fitness of a population only has a 2% chance of fixing.

Beneficial alleles can also bring neutral alleles along with them through linkage disequilibrium. Begun and Aquadro found this out.

Wright Calculated the probability of fixation of a beneficial allele as 2s and with that he found that the over all rate of evolution was k=4Nvs this means that an allele with 1% increase in the fitness of a population only has a 2% chance of fixing.

Beneficial alleles can also bring neutral alleles along with them through linkage disequilibrium. Begun and Aquadro found this out.

Recombination uses your Genes As Playing Cards

Recombination uses your Genes As Playing Cards

Through the process of meiosis crossing over switches alleles from homologous chromosomes of the organisms father and mother.

Then those are independently assorted, meaning that either the mother’s or the father’s chromosomes are transferred into the different cells independently of how the other chromosomes are lining up.

Recombination can also create new alleles by crossing over at incomplete gene loci.

Through the process of meiosis crossing over switches alleles from homologous chromosomes of the organisms father and mother.

Then those are independently assorted, meaning that either the mother’s or the father’s chromosomes are transferred into the different cells independently of how the other chromosomes are lining up.

Recombination can also create new alleles by crossing over at incomplete gene loci.

Horizontal TransferHorizontal Transfer

Margaret Kidwell found these sections of DNA called P elements that were transferred from Drosophila willistoni to Drosophila melanogaster.

These two fruit flies species are distantly related and can’t reproduce. However the P elements were still transferred into melanogaster through a mite that feeds on both of these species.

When the mite feeds it takes up material such as DNA and because P elements are transposons, they move around in the DNA, they are easily taken up into the mites and can be injected into the next fly it feeds on.

Margaret Kidwell found these sections of DNA called P elements that were transferred from Drosophila willistoni to Drosophila melanogaster.

These two fruit flies species are distantly related and can’t reproduce. However the P elements were still transferred into melanogaster through a mite that feeds on both of these species.

When the mite feeds it takes up material such as DNA and because P elements are transposons, they move around in the DNA, they are easily taken up into the mites and can be injected into the next fly it feeds on.

The end again but there is still a lot to do!

The end again but there is still a lot to do!