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
Which situation best demonstrates a recessive trait being expressed?
When two recessive alleles are inherited.
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.
- 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.
What are the chances of 2 heterozygote parents having a heterozygote?
25%