G8 - Pedigrees and Sex-linked Traits

Question 1

pedigree

Answer 1

a chart that traces the inheritance of a certain trait among members of a family

Question 2

Genetic Counsellors

Answer 2

construct and analyze pedigrees to help trace the genotypes and phenotypes of a family
This can be used to determine if and how any particular trait runs in a family
For example, expectant parents may want to trace how hemophilia, a blood clotting disorder, runs in the family to know if their child is at risk

Question 3

how are pedigrees used by plant and animal breeders

Answer 3

These charts can be used to track both desirable and undesirable traits
For example, if you have a racehorse from a long line of prize-winning horses, you may charge another farmer a higher “stud fee” because the offspring produced are more likely to have those desirable traits

Question 4

If an allele is inherited on an autosome we say that it’s under the control of…

Answer 4

autosomal inheritance

This type of inheritance affects both sexes equally and is not affected by the inheritance of sex chromosomes

Question 5

TRUE OR FALSE: If an allele is on one of the sex chromosomes, the gender of the individuals will affect the inheritance of this trait

Answer 5

TRUE

This is because females are XX and males are XY
We call these traits sex-linked

Question 6

If a genetic disorder is carried on the X chromosome we would say this is…

Answer 6

X-linked

Question 7

For X-linked If the disorder is recessive, even if a male only inherits one copy of the gene he will…

Answer 7

express the disorder because he is XY

Question 8

A father also cannot pass on an X–linked trait to his sons,

Answer 8

only his daughters

Question 9

EX of X-linked

Answer 9

red-green colour-blindness, hemophilia, and male-pattern baldness are all X-linked traits

Question 10

Y-linked disorders do exist but can only be passed from…

Answer 10

from father to son

Question 11

Why is there fewer Y-linked disorders

Answer 11

Y chromosome is much smaller and carries less genetic information than the X chromosome
Sometimes, Y-linked disorders may cause reduced fertility in males and may require medical intervention

Question 12

TRUE OR FALSE: SEX-LINKED RECRSSIVE TRAITS TEND TO BE MORE COMMIN IN XY GENOTYPES THAN XX

Answer 12

TRUE

Question 13

Sex-linked dom trait

Answer 13

-If there is 1 dominant allel then indivdual will have that trait