Sex-Linked Traits Flashcards
What are sex-linked traits?
Traits controlled by genes located on the sex chromosomes
What are most traits? What does this mean?
X-linked; It means the trait is carried on the X chromosome
What is tiny? What does that mean?
The Y chromosome is tiny, meaning not many genes on it (Y-linked traits are more rare)
Why are males more affected by recessive x-linked traits?
- This is because males have only one X chromosome
- There’s no other allele to dominate over the recessive allele
In an X-linked trait, what is the allele on the X chromosome?
Recessive
What happens if a male inherits the X chromosome from a mother who carries the recessive allele?
He will express the disorder because the Y chromosome cannot mask the effects
Who can a male not inherit an X-linked disorder from?
His father, since a father passes on a Y chromosome to a son
What is the only way a female expresses an x-linked recessive disorder?
A female must inherit two copies of the recessive gene, in order to express the disorder
What are some examples of x-linked diseases?
Red Green Colour Vision Deficiency
- X linked recessive
Hemophilia
- X linked recessive
- Inability to clot blood
Duchenne Muscular Dystrophy
- X linked recessive
- Causes muscle degeneration
Fragile X Syndrome
- X linked dominant
- Can cause mental and social disorders
Rett Syndrome
- X linked dominant
- Neurological disorder
Who is an Y-linked trait passed on from to?
Passed on from father to son
Compared to X-linked diseases, are there more or fewer of Y-linked diseases? Why?
There are fewer; Smaller and don’t carry as much genetic information
Why can males only be affected?
Allele is on the Y chromosome therefore males can only be affected
Are there carriers for Y-linked traits?
There are no carriers
What is an example of a Y-linked trait/disease?
Reduced fertility
