Chapter 16: Sex Chromosomes and Linked Genes

Question 1

What are x and y linked genes?

Answer 1

Females carry two X chromosomes (XX), while males carry one X and one Y chromosome (XY). Therefore, females carry two copies of each X-linked gene, but males carry only one copy each of X-linked and Y-linked genes.

Question 2

What are sex chromosomes and how are they unique?

Answer 2

Chromosome 23 is the sex chromosome.
They are unmatched chromosomes sharing minimal genes.

Question 3

What gender has more representation in X-linked diseases? Why?

Answer 3

X-Linked Diseases are more represented in Men (only one X, nothing to dominate a mutated X)

Question 4

Which gender has more representation in Y-linked diseases? Why?

Answer 4

Y-linked traits never occur in females, and occur in all male descendants of an affected male. (males are XY and females are XX)

Question 5

Which chromosome does not have a homologous chromosome? How can we use this when determining heritance or genetic variation?

Answer 5

The Y chromosome does not have a homologous chromosome.
(23 homologous pairs in females and 22 in males)

Question 6

Which chromosome does not have any crossing over events during Meiosis ?

Answer 6

Y-Chromosome does not have a homologous chromosome and will not have crossing over.

Question 7

How do dominant and recessive alleles play a role in which genes are expressed in children?

Answer 7

Males only have one X chromosome so if their mom carries it, they have a 50% chance of getting it.
Females have two X chromosomes so there may be a dominant allele that overrides the recessive one.

Question 8

What is the difference between Single-Gene Traits and Complex Traits?

Answer 8

Single-Gene Traits:
determined by variation at a single gene

Complex Traits:
influenced by multiple genes as well as by the environment