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Who was Gregor Mendel?
Father of Genetics
Where did Gregor Mendel live and work?
In Eastern Europe, Augustinian priest in the Monastery of St. Thomas in Brünn (Brno, Czech Republic)
What species did Mendel choose to conduct his experiments on?
Why did this species make such a good model to study inheritance?
How could Mendel be sure that all of the off spring produced were “by his design”
Peas because they are available in many varieties, they also had a short generation time, causing a large amount of offspring.
Mendel removed immature stamen from a plant before they produced pollen and dusted flowers with pollen from a separate plant
Mendel had several repeated findings explain:
The phenotypic ratio Mendel found in the offspring when he completed a monohybrid cross. What do the numbers stand for? If you need to use an example to effectively explain, you can use the trait of flower colour (P=purple, p=white) in snapdragons
The phenotypic ratio Mendel found in the offspring of a dihybrid cross. What do the numbers in the ratio stand for? If you need to use an example to effectively explain, you can use the traits of coat colour (B=brown b=white) and coat texture (R=smooth, r=curly) in guinea pigs
3:1 ratio which means that each offspring has the probability of 75% chance of showing a dominant trait and 25% chance of showing a recessive trait
9:3:3:1 ratio which means that each offspring has 9/16 chance of showing a Dominant trait for both trait,
3/16 chance of showing a dominant trait for 1 trait but recessive for the other trait.
3/16 chance of showing a recessive trait and dominant trait
1/16 chance of showing a recessive trait for both
Explain the Law of Independent Assortment
states that the allele of one gene separates independently of an allele of another gene.
Explain the Law of segregation
when separate the two alleles if they have a dom. & rec. than they will end up in different gametes.
In guinea pigs, short hair is dominant over long hair. A female guinea pig with short hair but whose father had long hair is mated with a male whose parents were both short-haired, but who has long hair. Using a Punnett square, predict the genotypic and phenotypic ratios of their offspring.
You are working as a genetics specialist in a hospital. A couple comes to you saying they want to have a baby, but they want the baby to have freckles and neither of the potential parents has this trait. You take out your trusty, always useful, grade 11 Biology textbook and find out that freckles are inherited as a dominant trait. What news can you now give the anxious couple? Support this wise knowledge you have imparted by setting up a Punnett square to prove your point.
Incomplete dominance
It supports the blending hypothesis. When the two traits mix and create a new offspring that doesn’t look like either of them. neither of them take dominance of the trait therefore its incomplete
Multiple alleles
When you have 3 or more options to fill in 2 spots on a gene
Co-dominance
two alleles affect the phenotype together but in separate distinguishable ways
Pleiotropy
1 gene controls many phenotypes
Polygenic Inheritance
the inheritance of a trait controlled by more than one genes
Epistasis
When a gene at one locus alters the phenotypic expression of a gene at a second locus.
When one gene doesn’t allow a trait to be expressed
Explain how a trait can be dominant but uncommon in a population
It can be dominant however it could look daunting for a human to find attractive so the trait in a person never has an offspring or is killed at birth.
Recessive Genetic disorders
Explain the difference between an affected individual, carrier, and an unaffected individual
Affected individual: recessive for both alleles which means they have the disorder
Carrier: They are heterozygous which could mean that they have mild symptoms for the disorder or just a carrier
Unaffected person: they are homozygous dominant for this recessive genetic disorder
Recessive Genetic Disorders
Explain the genotypes affected by this disorder and dive an explain of a recessive disorder from class
Compare and contrast 2 with each other
Incomplete dominance
Multiple alleles
Co-dominance
Pleiotropy
Polygenic inheritance
Epistasis
Incomplete dominance
It supports the blending hypothesis. When the two traits mix and create a new offspring that doesn’t look like either of them. neither of them take dominance of the trait therefore its incomplete
Multiple alleles
When you have 3 or more options to fill in 2 spots on a gene
Co-dominance
two alleles affect the phenotype together but in separate distinguishable ways
Pleiotropy
1 gene controls many phenotypes
Polygenic inheritance
When a single gene affects several phenotypic characters
Epistasis
When a gene at one locus alters the phenotypic expression of a gene at a second locus.
When one gene doesn’t allow a trait to be expressed
Dominant genetic disorders
Explain why there is no such thing as a carrier when it come to dominant genetic disorders
Because if its dominant it can’t be hidden like a recessive trait can, which means you either show it or you don’t have it
Dominant genetic disorders
Explain the genotypes affected by this disorder and give an example of a dominant disorder from class
Nature vs. Nurture
be able to explain the nature vs nurture debate, include the findings of current science
Nature: Human characteristics are the results fo genetics
Nurture: Human characteristics are the result of environmental factors
What does sex linked mean in genetics
the trait is located on the XY chromosome
Be able to complete a punnett square for a cross of a single sex linked trait
explain why males are more likely to express a sex-linked disorder than females are
because if they mum has the disorder and the dad doesn’t that the daughter becomes heterozygous for the disorder, but because the only thing that the sons are getting from there father is a Y the disorder will be the only thing that appears
SRY for sex-determining region of Y
Explain what happens to the second X chromosome in the nucleus of the cell in women?
what is this called
explain the coat colour calico cats
explain what is meant by women are mosaic
Barr bodies, which makes the x chromosome inactive.
Because the cat has different x chromosome one genetic coat colour from mum and one from dad, some don’t have a barr body which causes the fur to be orange. For some of the alleles will have the black fur.
how do you identify males and females on a pedigree?
how do you know which individuals are affected?
circles are female
coloured circle - female and affected
square are male
coloured square - male and affected
how would you know if a pedigree was describing an autosomal or sex-linked trait?
if there is a father to son transmission then it is autosomal, if theres more males that are affected then female and there is a skip between generation it is recessive
Heterozygous
When an individual has one each of two different alleles for a given trait
Homozygous
When an individual has 2 of the same allele for a giving trait
Dominant
`overshadow the recessive trait and in most cases mask the recessive trait.
A gene or trait that is expresses over another gene or trait
Recessive
A gene or trait that is masked by a dominant gene or trait, if one is present
the trait that is masked by the dominant trait or will become a true breeding
Gregor Mendel
the father of genetics
Pure Bred
allels which are the same and will produce the same off spring
Hybrid
The offspring of a cross where one parent was homozygous dominant and one parent was homozygous recessive for a trait.
Barr Body
Barr bodies are condensed, inactive X chromosomes found in the nuclei of female mammalian cells. Barr bodies are formed as a result of X-chromosome inactivation, a process that occurs randomly during embryonic development to equalize gene expression between males and females.
Punnett Square
to predict the outcome of a breeding experiment on a particular character
Genotype
The genetic makeup of a trait (not seen with the naked eye)
Phenotype
something that can be physical seen
Sex-Linked
located on the x or y chromosome
Autosomal
a disorder which is not located on the x or y chromosomes
Complex Inheritance
Complex inheritance refers to the inheritance patterns that involve multiple genes and interactions between them. It can result in a wide range of phenotypic outcomes that are not easily explained by simple Mendelian inheritance.
Examples of complex inheritance include polygenic traits, where multiple genes contribute to a single trait, and gene-gene interactions, where the effects of one gene depend on the presence or absence of another gene. Complex inheritance is often influenced by environmental factors as well.
Incomplete Dominance
Incomplete dominance
It supports the blending hypothesis. When the two traits mix and create a new offspring that doesn’t look like either of them. neither of them take dominance of the trait therefore its incomplete
Multiple Alleles
Multiple alleles
When you have 3 or more options to fill in 2 spots on a gene
Co-dominance
Co-dominance
two alleles affect the phenotype together but in separate distinguishable ways
Pleiotropy
Pleiotropy
1 gene controls many phenotypes
Polygenic Inheritance
Polygenic inheritance
When a single gene affects several phenotypic characters
Epistasis
Epistasis
When a gene at one locus alters the phenotypic expression of a gene at a second locus.
When one gene doesn’t allow a trait to be expressed
Note
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