Evolution works by what?

Genetic transmission

Apart from genetic transmission, how else can information be transferred?

In addition to genetic transmission, information can be transferred by epigenetic, behavioural, and symbolic means

How would it be possible for behaviours that your parents, or even grandparents, engaged in to influence you?

Through the process called epigenetics. This is not actually the result of changes in your genes but the changes in the mechanisms that turn your genes on and off.

In his theory of natural selection, what did Darwin stress?

Darwin stressed variations in heritable traits and the manner in which different environments place specific traits at an advantage.

Which specific unit involved in the process of evolution (and more particularly natural selection) was Darwin unaware of?

The gene

What is the purpose of the gene?

Genes carry the instructions that direct the expression of particular traits.

What is one view in the history of science for the loss of interest in evolutionary approaches during the first half of the 20^th century?

One view is that it was due to the lack of an articulated connection between genetics and evolution

Although genes and evolution were unknown to each other, at about the same time Darwin was working, the initial mechanisms by which genes work was being described by whom?

Gregor Mendel

Where did Mendel work?

He worked in a monastery in a city near Vienna – which is now part of the Czech Republic

During the latter part of the 19^th century, the work of Darwin and Mendel and their followers occupied parallel tracks. It was with the publication of which book, written by whom did these two lines of research come together in what is now referred to as the modern synthesis?

Genetics and the Origin of Species, 1937 – written by Dobzhansky

Though ADHD is heritable, which behaviour that is somewhat related to this is not?

Aggressive and disruptive conduct

Early Alzheimer’s disease is related to a particular gene on which chromosome?

Chromosome 14

How come traditional European restaurants, but not Asian restaurants, have many dairy products such as cheese and creamy sauces?

Because Northern Europeans have a gene that enables them to continue digesting milk products after the traditional time of weaning. (A person with such a gene would have had an advantage in Northern Europe because dairy products are a high quality food source and over time, probably less than 10, 000 years, that advantage would have allowed these genes to be passed on to almost all the European population.

Agricultural societies and hunter-gatherers in arid environments who consume food with large starch content have accumulated extra copies of a particular gene. What is this gene called and what is its influence on the body?

·         The gene is called AMY1

·         It is related to a protein in one’s saliva that breaks down starch

*Rainforest hunter-gatherers and other groups that eat foods with less starch do not show these extra copies of the gene. Overall, these types of studies suggest that in evolutionary time, diet can play a role in genetic selection.

Describe one study that looked to answer the question, “how many generations does it take for genes to change?”

One study showed that ethnic Tibetans split from Han Chinese fewer than 3, 000 years ago. Tibetans have the ability to work at high altitudes with low oxygen levels. This suggests that genetic mutations may have been involved. The Tibetan study compared the genomes of 50 Tibetans and 40 Han Chinese. One of these genes is referred to as EPAS1 and is also seen in individuals with high-level athletic performance. This genetic change happened in fewer than 3, 000 years.

Individuals with high-level athletic ability carry which common gene with the Tibetans and Han Chinese?

EPAS1

Genes can be expressed in either a positive or a negative way. Provide an example for both.

·         Positively: strong immune system or a long life

·         Negatively: cancer or alcoholism

A gene is simply a part of the total length of what?

DNA

What is a synonym for what?

Sequence of DNA

What do genes (sequences of DNA) tell the body how to do?

How to manufacture particular proteins

In newspaper and television rather explaining the complex turning on and off of our genes is often ignored, especially in relation to disease, what are we led to believe?

What we are led to believe instead is that particular genes produce particular disorders.

Very few traits, with the exception of what, are displayed by genes without a complex input and interaction with the environment?

Blood type

How does the appearance of the Squinting Bush Brown butterfly change depending of the season in which they were born?

·         If born in the rainy season, it is brightly coloured

·         If born in the dry season, it is gray

The side blotched lizard of the Mojave Desert will have different colorings depending on its environment. Explain.

·         It will be black if it is raised in a habitat of black lava flow

·         It will be lighter if it is raised in light desert sand

What are the advantages of environmental coupling (ex: animals that camouflage into their surroundings)?

·         Offers a  means of protection

·         Promotes health

·         Promotes well-being (ex: With some disorders, simply changing the environmental conditions in terms of the types of food a person eats can actually prevent the negative outcomes of a genetic disorder.

If you are a mouse, how can your mother’s diet influence you?

What your mother ate could influence the colour of your fur and the diseases you would be susceptible to.

What gives infants the ability to digest lactose?

A certain enzyme in the milk of their mothers, which work with the infant’s own genes to break down the lactose. Actually, it is a single dominant gene that is involved in the production of the enzyme that breaks the milk sugar down. (This is a striking example of the manner in which cultural and environmental change can be mapped along with genetic change in that of lactose)

If you are lacking in the enzyme that breaks down milk sugar, what can happen?

Cramps, diarrhea, and nausea.

Adults from which regions are typically able to continue drinking milk?

·         Europe

·         Sub-Sahara Africa

·         India

How did it come to be that some people are lactose tolerant?

It appears that when cattle were first domesticated some 9,000 years ago, humans began to eat their meat and drink their milk. Some of the people living at that time had a mutation that kept the gene involved in producing the enzyme that enabled the individual to digest milk sugar permanently switched on. Giving that these individuals did not become sick from drinking milk, they had a certain advantage, particularly in difficult times such as droughts.

It is estimated that those who carried the gene causing them to be lactose tolerant were able to leave how many more times as many children as those who were lactose intolerant?

About 10 times more (this is demonstrated by today by the fact that almost all of the citizens of the Netherlands and Sweden, the area where cattle were originally domesticated in Europe, are lactose tolerant.

Is it believed that lactose tolerance developed dependently or independently in different parts of the world?

Independently

What does the genotype consist of?

It consists of what is inherited through the sperm and egg at the moment of conception

What does the phenotype represent?

It represents the observed traits of the individual including morphology, physiology, and behaviour.

Has psychology traditionally focused on the genotype of the phenotype?

The focus of psychology has largely been the study of the phenotype.

What is the genome?

The complete set of human genes

What did Max Delbruck (1949) – one of the founders of the field of molecular biology – suggest we are looking at when we look at living cells?

He suggested that what we are seeing is the result of billions of years of experimentation

By the time we are born, about how many cells do we have?

About a trillion cells

How can cells be differentiated?

By structure and function

In which part of the cell is the genome contained?

Inside the nucleus

About how many genes are contained within the genome?

About 20,000 genes along with some additional material (though different species have different amounts of genes – the basic mechanism is the similar across species)

What is the job of the gene?

To lay out the process by which a particular protein is made. Said technically, each gene is able to encode a protein.

Functional proteins in the form of enzymes are able to do what?

They are able to make metabolic events speed up

What are structural proteins able to do?

They are involved in building body parts

Are functional or structural proteins responsible for the creation of spider webs, butterfly wings, and feathers?

Structural proteins

Proteins are made by our cells from some 20 __________   __________

Amino acids

Although the cells in the body carry the full set of genetic information, about how much – related to the function of the cell – is expressed at any one time?

1.       A gene does not produce a protein constantly

a.       A protein is produced in the context of a complex physiological system influenced by internal bodily processes and by events in the external environment.

b.      We can think of a gene being turned on (producing the protein) or turned off (not producing the protein) relative to specific events.

2.       The environment in which a person develops and lives plays an important role in gene expression.

3.       What we view in human processes represents not only a complex interaction between a person’s genetic makeup and the environment, but also a complex expression of many genes.

4.       Genes do not produce behaviours. Rather, genes encode a protein, which can have implications for actions, feelings, and thoughts. Although there are implications, it does not necessarily follow that the behavioural outcome was the result of a genetic plan alone.

·         In 1868, almost 100 years before Watson and Crick, a physician named Johann Friedrich Miescher collected cells from the pus of open wounds as well as the sperm from fish. Miescher was interested in identifying the chemical composition of the nucleus of the cell. What he discovered was an organic compound with the properties of an acid, which he called nuclein. Today, we know nuclein as DNA, the storehouse of information concerning heritable traits.

·         Later, during the first part of the 20^th century, the basic chemistry of nuclein was worked out, with two forms differentiated in terms of sugar composition. Those forms were DNA and RNA.

·         The work that led to the discovery of the sturture of DNA included the work of Linus Pauling describing chemical bonds. Later, Pauling and R.B. Corey measured a helical structure, and Maurice Wilkins and Rosalind Franklin created X-ray diffraction photographs of DNA.

·         With the developments of physical chemistry and X-ray crystallography, the stage was set for Watson and Crick’s discovery. As this this point, the challenge was for Watson and Crick was to create a structure that conformed to the laws of physical chemistry and, at the same time, could function as a gene, the carrier of heredity.

·         The answer was a double helix, with each individual rung being made up of a pair of nucleotides that were not similar.

“It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material.”

1.       Its ability to reproduce itself

2.       Its role in producing proteins

This is accomplished in two steps.

1.       The information in DNA is encoded in RNA

2.       This information in RNA determines the sequence of amino acids, which are the building blocks of proteins

Though RNA and DNA are very similar, what is a clear difference between the two?

·         Adenine

·         Guanine

·         Thymine

·         Cytosine

What are the four nucleotide bases (adenine, guanine, thymine, and cytosine) generally referred to?

·         Adenine -  A

·         Guanine – G

·         Thymine – T

·         Cytosine – C

Chromosome

·         The beginning of a DNA strand is called 5’ (five prime)

·         The end 3’ (three prime)

The two strands of the double helix contain the same information, albeit in _________   _________

Opposite directions (that is, one strand in the DNA molecule runs 5’ to 3’, and the other runs 3’ to 5’)

What is the measurement of each full twist of the DNA double helix?

·         Adenine

·         Guanine

·         Uracil

·         Cytosine

What is the RNA code?

It a sequence of three of the bases along a single RNA strand – which specifies one particular amino acid

What do the sequences of three bases along RNA strands determine?

They determine which of 20 amino acids are put together to form a specific protein

What is the table of correspondences between codons and amino acids called?

What are the sequences that signal the beginning and end of the protein chain called?

Change in the rate at which RNA is transcribed controls the rate at which genes produce what?

·         The particular organism they were studying was the bacterium Eschrichia coli. This organism can switch from a diet of sugar (glucose) to milk sugar (lactose) if glucose in its environment becomes scarce. To make this happen, these bacteria must produce an enzyme that breaks down lactose.

·         What Monod and Jacob discovered was that an environmental event, the presence of lactose and the absence of glucose, would case the genes to turn o n and the enzymes to be produced. When this environmental condition was not present, these enzyme-producing genes were inhibited and thus not allowed to turn on. That is to say, the transcription of the DNA into RNA and the resulting proteins were repressed when the environmental condition of lactose presence and glucose absence existed.

·         Language

·         Code

·         Blueprint

·         Plan

·         Book (because the chemical composition of DNA is designated  by letters; chromosomes analogous to chapters; genes analogous to particular paragraphs)

·         Selfish Gene (used by Richard Dawkins)

·         Recipe (used by Matt Ridley in Nature via Nurture)

DNA can be illustrated in different ways - name three ways.

·         A model showing complementary base pairing in the interior of the molecule

·         A model of a double helix wound around a central axis

·         A model that shows the relative size of atoms in the molecule

In terms of behaviour and experience, the production of proteins can be transitory. For example: 

Touching a rat’s whiskers causes changes in gene expression in the cells of the sensory cortex of the brain. This is a momentary change.

In terms of behaviour and experience, the production of protein can be long-term. Provide an example.

·         Ex1: When a songbird first hears the specific song of its species, a particular set of genes comes into play that, when once set, determines the song produced by that bird for its entire life. This process has been mapped by a variety of researchers.

·         Ex2: Raising mice in an enriched environment – that is, one with lots of toys and stimulation – will cause increased gene expression in genes that are associated with learning and memory

How do we know which genes are involved in producing a given protein?

·         Comparing a treatment group to a control group

·         To actually change the genes in a particular organism (ex: so-called “knockout” mice are genetically engineered mice in which particular genes have been turned off by breeding them in specific ways.

o   Research shows that simple genetic changes made experimentally in animals can result in protein changes that influence social behaviour. Some examples of such behaviours are increased fear and anxiety, hyperactivity, and even increased alcohol consumption when stressed.

The “homeotic genes” or “Hox genes”

1.       They lay out the basic body plan during development for all species. The same Hox genes that determine where the body parts go in the mouse also do so in the fly and in the giraffe.

2.       Hox genes can be swapped between species with little obvious effect on physical development.

How do the Hox genes determine where the body parts go during development?

They do this by switching on other genes during development. The location of these genes along the chromosome corresponds to the body from front to back. That is, the first Hox gene develops the front aspects of the body, continuing in order until the final Hox gene develops the posterior aspects of the body.

What is a DNA molecule along with the proteins that are attached to it called?

Does each chromosome look identical or unique?

Chromosomes are numbered in approximate order of size, with 1 being the largest and 22 being the smallest.

What are the first 22 sets of chromosomes called?

·         q (long arm)

·         p (short arm)

·         The lowest numbers would be nearest the chromosome

·         The highest numbers would be farthest from the chromosome

The chromosome number comes first, followed by the long or short arm designation, and then the banded region number.

·         EX: You would use 7p22 to represent region 22 on the short arm of chromosome 7

How many chromosomes does a dog have?

A way of representing the chromosomal contents of a cell, including the number of chromosomes followed by a description of the sex chromosomes.

·         Male – 46 XY

·         Female – 46 XX

On any one chromosome there can be anywhere from a few hundred to almost how many genes?

In 1990, the Human Genome Project was started with which goal?

With the goal of cataloging the genetic information found in humans

To date, what has the Human Genome Project accomplished?

About how many cells are there in a fully grown human body?

Before division, DNA is replicated by an unwinding of the double-stranded molecule. As this happens, a new complementary strand is assembled piece-by-piece on which part of the chromosome?

The DNA that is duplicated is generally exactly the same as the original DNA. However, there are times that slight variations develop. Is there any mechanism that accounts for these inconsistencies?

·         The process is called meiosis

·         The production of gametes is somewhat different from that of mitosis, in that the DNA must be replicated and the diploid number of chromosomes must be reduced to haploid.

·         A germ cell duplicates its DNA. Each duplicated chromosome now consists of two DNA molecules. As in mitosis, these remain attached at the centromere and are called sister chromatids. Unlike mitosis, however, these chromosomes proceed through two consecutive divisions.

·         Each duplicated chromosome migrates with the cell to line up with its partner

·         Each chromosome becomes connected to its homologue so that all four chromatids are intimately aligned.

·         Thus, we have four DNA molecules, which may later develop into four gamete cells and function in sexual reproduction. However, before that takes place, the chromosomal material is almost randomly exchanged between homologues. This process of gene swapping is referred to as recombination. After this process, the chromosomes are no longer identical to those inherited from the parents. Rather, each of the four strands of recombinant DNA contains some material originating from the father and some from the mother.

How many combinations of chromosomes from a mother and father are possible each time a human germ cell gives rise to sperm or egg? What would be the reality without this process?

·         2²³

·         Without this process everyone would be exactly like his or her parents

Which proportion of genes allow for variation?

What is the technical term for the unique molecular form of the same gene?

When a person has two copies of the same allele, what are they referred to as?

·         Peas are a self-fertilizing plant, which means that the male and female aspects needed for reproduction develop in different parts of the same flower. Therefore, successive generations of peas are similar to their parents in terms of particular traits such as the color of their flowers.

·         Mendel wondered what would happen if he cross-bred pea plants that have one particular trait (e.g., white flowers) with those of another trait (e.g., purple flowers).

·         In performing these experiments, Mendel was able to explain the manner in which information is transmitted from parent offspring. Mendel accomplished this by transferring pollen from one plant’s flower to the flower of another plant.

o   In one experiment, Mendel found that when he combined peas with white flowers with those with purple flowers, the next generation had all purple flowers. Allowing this generation to self-fertilize brought forth plants that had purple flowers but also some that had white flowers. Mendel explained these findings by suggesting that a plant inherits information from each parent, the male and female aspect.

·         He determined the basic principle that there are two elements of heredity for each trait. He assumed that one of these elements can dominate the other, and if it is present, then the trait will also be present. For the recessive trait to appear, both of these non-dominant elements must be present.

o   These ideas are referred to as the “law of segregation” or “Mendel’s first law”

·         He also realized that the inheritance of the gene of one trait is not affected by the inheritance of the gene for another trait.

What is the advantage of the Punnett-square method?

What is the general mathematical rule for any number of gene pairs?

What are two main points that Mendel’s mathematical calculation allowed him to understand about inheritance and traits?

1.       That traits were inherited as if they were separate units

2.       It did not matter whether the traits came from the male or female parent; they combined in the same manner.

Which modern discovery violates Mendel’s second law?

1.       Genes on the Y chromosome are expressed only in males

2.       Genes on the X chromosome may be expressed at a higher level in females

His discovery of “blood typing” helped us to understand who could receive types – A, B, AB, and O.

·         Chromosome 9

·         It has three alleles: I^A, I^B, and I^O

How will type AB individuals possessing both the A and the B antigens react to blood of either type A or B?

Because they lack both A and B antigens – they will not be rejected by any other blood type.

People with type O blood are less likely than those with type A blood to develop which disease?

They are less likely to develop cancers of the esophagus, pancreas, and stomach

The distribution of the type B allele suggests a migration of people from Central Asia into Europe

Looking at the maps of blood types, what can be concluded about the ages of different blood types?

How can sickle cell amnesia have positive, negative, and neutral effects?

It depends on the situation

·         Positive: Protects against malaria

·         Negative: sickle cells can rupture and limit necessary oxygen for the body and result in a variety of problems ranging from anemia to poor physical development to failure of organs such as the kidneys

·         Neutral: Might not affect the individual at all

Sickle cell amnesia is most often seen in individuals whose ancestors live in which parts of the world?

All regions in which malaria exists – it is assumed that its presence is a result of natural selection

·         West Africa

·         Lowland regions of Sicily

·         Cyprus

·         Greece

·         Middle East

·         India

1.       The garden plant hydrangea will produce different flower colors depending on how acidic the soil is (the alleles are identical but interact with an environmental factor)

2.       A certain type of rabbit will change fur colours depending on the temperature of its different body regions (ex: The Himalayan rabbit’s ears, which are cooler, will have darker fur than the warmer body regions)

·         A single change in an 861-nucleotide-long gene that produces the protein hemoglobin

·         Hemoglobin enables red blood cells to carry oxygen

·         Some people have a variant with a single change in the 15^th base pair of the β-hemoglobin gene. This variant result in a slightly different amino acid sequence for the hemoglobin protein, which tends to protein, which tends to produce molecules that stick together in a rod-shaped arrangement when oxygen is low.

·         This arrangement causes the red blood cell to collapse and assume the shape of a sickle (the farm implement for cutting grain)

·         The aspect that controls this aspect of hemoglobin is located on chromosome 11 and is recessive

What is “reverse translation”?

These types of research suggest that behavior and experiences at critical periods could later influence characteristics for generations to come.

·         The diet of a mouse mother before conception can influence the hair color of her infants and even her grandchildren

·         A mouse will develop a diabetes-like disease if her father’s diet before her conception was high in fat

·         If a mouse father is overweight, then gene activity in the pancreas of his offspring is abnormal – because the pancreas makes insulin, which regulates blood sugar, the father’s obesity may set up the possibility of future diabetes. Likewise, if a father’s diet results in an underweight condition, genes in the liver associated with fat and cholesterol synthesis are more active in his offspring

·         One study suggests that whether a human father smoked early in life was associated with his sons being heavier in weight at age 9

How is mitochondrial DNA generally inherited?

It is generally inherited only from the mother (this is clearly a violation of the Mendelian inheritance)

·         This helped researchers to discover the genetic link of certain disorders that show maternal or mitochondrial inheritance patterns.

What feature of mitochondrial DNA gives it a special application in the study of evolution?

Who lived some 150, 000 to 200,000 years ago. This female has been referred to as “Eve”.

When later genetics of a larger genetics of a larger population can be traced to a limited number of individuals – what is this referred to as?

The founder effect can be seen in modern-day communities such as the Amish in Pennsylvania, in which a few individuals created a community that has remained isolated, with intermarriage being common.

·         If they are identical, we would assume that the individuals are related in some manner

·         If they are dissimilar, we would assume that their last common maternal ancestor live a long time ago

True.

·         EX: you could ask which animals in the wild are most like your pet dog and at what point did they become domesticated. The answer is that grey wolves show a close relationship to dogs.

The initial domestication of dogs from wolves appears to have begun 15, 000 years ago in Southwest Asia, although dogs and wolves may have separated some time earlier.

What is the history of the bacterium that is responsible for stomach ulcers?

This bacteria is found in the stomachs of half the humans on earth. It appears to have originated in Africa and also seems to have spread out of East Africa around 58, 000 years ago, which is one estimate of the being of human migration. Today some five different version of the bacteria can be found.

                *Researchers suggest that these genetic bacteria markers are actually better than traditional human genetic markers for determining lineage.

One famous example is that of Genghis Khan. He slept with a lot of the remaining women from the areas that he conquered and with his vast amounts of concubines. Khan and his sons were characterized as being highly prolific. Researchers have examined the Y chromosome of individuals from Asia. In the area that would have been the empire of Genghis Khan, they found a Y chromosomal lineage with several unusual features, which they refer to as “star-cluster chromosomes”. It was found in about 8% of men in that region, but less than ½ of 1% of men worldwide. They concluded that it originated about 1, 000 years ago and that its rapid spread could not have happened by chance alone.

It refers to the possibility that individuals with different genotypes may respond to the same environment in different ways. (ex: a study of how children with different genotypes respond to the traditional school system)

In work with more than 100 pairs of twins, these researchers found that about 70% of the variance in IQ could be associated with genetic factors. However, if the child’s family lived in poverty, the degree of association dropped drastically. Although it is not surprising to find IQ or temperament to have genetic associations, it was intriguing to see that the leisure time interests of each twin in the pair were similar, whether the twins were reared together or reared apart.

Explain the type of study referred to as “linkage analysis”.