Genetics Vocab
The scientific study of heredity
Genetics
Which type of trait can be masked by another trait?
Recessive
What do we call the physical appearance of a trait in an organism?
Phenotype
Does not have a Y chromosome
Female
A pedigree shows a horizontal line between a male and female. What does this represent?
Mating/produced offspring
The passing of traits from parent to offspring
If a dominant allele is present in an organism, what happens to the recessive allele?
It is not expressed
In a plant G= green pods and g=yellow pods.
What is the phenotype of genotype Gg?
Green Pods
Ture or False: Fathers will always pass X-linked traits to all of their sons.
Father's can only give the Y chromosome to their sons (the sons will not inherit any of the father's X-linked traits)
What does a half shaded individual on a pedigree represent?
Carrier of a trait
An individual with copies of the SAME type of allele
Homozygous
What would the genotype of a green pea be? (yellow= dominant; green = recessive)
yy
An organism has the genotype aa.
What term best describes this genotype?
Homozygous Recessive
A male with normal vision is married to a female who also has normal vision. One of their sons is colourblind. What are the genotypes of the parents?
Male: XAY
Female: XAXa - carrier of the colourblind trait
A trait affects males and females equally. Is the trait autosomal or X-linked?
Autosomal
Process of humans exerting selective pressures on a population in order to improve or modify particulate desirable traits
Artificial Selection
A trait appears in every generation of a family.
Is this trait more likely dominant or recessive?
Dominant
In mice, B = black fur and b = brown fur.
Two heterozygous mice are crossed (Bb × Bb).
What genotype produces the recessive phenotype?
bb
Why are there more colourblind males than females?
Females get 2 X chromosomes and both would have to have the recessive trait to show colourblindness. Males only get 1 copy of the X chromosome, therefore they would show colourblindness if they had one copy of the trait.
In a pedigree, you notice the following patterns:
- males are more affected than females
- the trait skips a generation
- the trait is never passed from father to son.
What is the pattern of inheritance?
X-linked recessive inheritance
A chart or "family tree" that tracks which members of a family have a particular trait
Pedigree
Two parents do not show a certain trait, but their child does show it.
Is the trait dominant or recessive?
Recessive
In humans, albinism is a recessive trait (a), while normal pigmentation is dominant (A).
A man with normal pigmentation has a mother who is albino.
What is the man’s genotype?
Aa
In squid, eye colour is an X-linked trait. Red eyes (R) are dominant over white eyes (r). Squidward (white eyes) falls in love with red-eyed Squidonna. Squidonna is intrigued by Squidward's white eyes because everyone in her family has only had red eyes (she has never seen a white-eyed squid before. Squidward and Squidonna want to have white-eyed children in the future. What are all the possible genotypes and phenotypes of their children?
All their children (male and female) will have red eyes.
In a pedigree, you notice the following trends:
- both males and females are affected, but it is more common in females
- all the affected sons have affected mothers
- all affected fathers passed the trait to all of their daugthers.
What is the pattern of inheritance?