*Unit 5: Sex-Linked Crosses and Pedigrees Flashcards
Meiosis and Genetics
Sex-linked genes
Genes found of the X Chromosome
_____ are XY.
Males
_____ are XX.
Females
How many copies of genes do males have on the X Chromosome?
1 copy
How many copies of genes do females have on the X Chromosome?
2 copies
Recessive genes on the X chromosome show up more in _____.
males
Hemophilia
A disorder that causes blood to clot incorrectly, causing patients to bleed from minor cuts
Hemophilia is common in royal families because of _____.
inbreeding
Red-green color blindness is most common in _____.
males
List human examples of sex linkage.
~Hemophilia
~Red-green color blindness
~Male pattern baldness
What are the parent genotypes of a heterozygous red-eyed female and a red-eyed male?
X(^R) X(^r) * X(^R) Y
Pedigree
Shows how a trait is passed down in an family
Carrier
~Indiviual who has 1 copy of a recessive allele
~doesn’t have disease
~Not always shown on pedigrees
Pedigree symbol for female.
A blank/white circle
Pedigree symbol for male.
A blank/white square
Pedigree symbol for affected female.
A filled in/black circle
Pedigree symbol for affected male.
A filled in/black square
Pedigree symbol for female carrier.
A half white, half black circle
Pedigree symbol for male carrier.
A half white, half black square
If a trait is seen more in males, the gene is _____.
sex-linked
If a trait is relatively even between males and females, the gene is _____.
autosomal
If a person has a disease and neither parent had the disease, it must be _____.
recessive
If carriers in a pedigree are shown, it must be a _____ trait.
recessive