non-mendelian inheritance Flashcards
codominance
both alleles are expressed, no dominant nor recessive alleles, heterozygous has both, homozygous has one trait
incomplete dominance
creates a blend of alleles, neither allele is completely dominant nor completely recessive, heterozygous has a mix of traits, homozygous has one
white feather chicken mates with black feather chicken, makes offspring covered in both white+black feathers. what inheritance is this
codominance
white feather chicken mates with black feather chicken, makes offspring covered in grey feathers
incomplete dominance
sex linked
genes on sex chromosomes are called sex linked genes, the X chromosome affects many traits, passing of traits from parents to offspring through sex chromosomes, Y chromosomes affect only male characteristics
a heterozygous individual that is a carrier is dominant or recessive
recessive
Cystic fibrosis is a recessive disorder. What genotypes have the disease
cc- affected
Cc- carriers
Dominant disorders have a _% chance the children will have the disease with only 1 parent who has it
50
how are genotypes for incomplete dominance and codominance written and why?
they are written with superscript letters because there is no dominant allele and no recessive allele
polygenic inheritance
when a trait is controlled by more than one gene, does not have a genotype of just 2 letters, ex: hair color
multiple alleles
different versions of a gene, each allele codes for a different variation of the trait
conditions necessary for someone to be a carrier for a genetic disorder
Mutated gene has to be recessive, parent has to be heterozygous for that trait carrying at least one copy of the mutated gene and one copy of the normal
what does empty square represent on a pedigree
male that doesn’t have the trait
what does a filled square represent on a pedigree
male that has the trait
what does a filled circle represent on a pedigree
female that has the trait
what does a empty circle represent on a pedigree
female that doesn’t have the trait
how do you identify dominant inheritance
at least one parent has the trait and either all of the children or most of the children have the trait
how do you identify recessive inheritance
both parents don’t have the trait (heterozygous) but give birth to a child with the trait
how do you identify sex linked inheritance
pattern with the genders (most likely boys) that have the trait, either no male carriers or if there is a male with the disorder, the genetics is only passed down to their daughter
how many chromosomes present in normal cell
46, 23 pairs
clues a karyotype is not normal
Chromosomes missing, some abnormally shaped, extra chromosomes
processes that occur resulting in abnormalities in a karyotype
nondisjunction, deletion, inversion, translocation, duplication
what is nondisjunction
nondisjunction- chromosomes don’t separate normally during meiosis resulting in pairs having too many or too few
what is inversion
inversion-segments of chromosome breaks off, flips around, and reattaches to the chromosome,
what is duplication
duplication-segment of a chromosome is duplicated, resulting in too large of a chromatid
what is translocation
translocation-segment of a chromosome is broken off and attaches to another chromosome, leading to abnormal chromosome shapes
A blood, B blood, AB blood, O blood genotypes
A: IAIA or IAi, B: IBIB or IBi, AB: IAIB, O: ii (written in superscripts)
A single gene that specifies coat color in horses is called the H gene. The H gene has four common alleles, each codes for a different color in the coat of the horses. Which type of inheritance is represented by the H gene in horses?
multiple alleles
Two people with type AB blood mate and have offspring. What proportion of their children will have type O blood?
0% because neither one of them carry the recessive O allele.
Two people with type AB blood mate and have offspring. What proportion of their children will have type A blood?
25% because each of them has one A allele.
In humans, hair texture exhibits incomplete dominance. The gene for curly hair (H) is incompletely dominant to the gene for straight hair (S). Individuals that are heterozygous (HS) have wavy hair. Two heterozygous parents have a child. What is the chance that the child will have wavy hair?
1/2
When cattle with solid white coats (W) are mated to cattle with solid red coats (R), the offspring are roan (WR), meaning they have coats containing both white and red hairs. The roan coat is an example of codominance. A farmer mates two roan cattle. What is the chance that their offspring will be solid red?
25%
When a black chicken mates with a white chicken, all of the offspring are covered in black feathers. What type of inheritance is exhibited by the chicken’s feather coloring in this example?
complete dominance
A chicken with the sex chromosomes ZW is female, and ZZ is male. Which gamete determines the offspring’s sex and why?
The female, because of the W chromosome
In Drosophila flies, eye color is sex-linked. The allele for red eyes (X^W ) is dominant to the allele for white eyes (X^w). A male fly with red eyes X^W Y and a carrier female X^ W X^w are mated. What is the probability that the female offspring will have white eyes?
0%
Hemophilia is an X-linked recessive condition in which blood does not clot properly. Queen Victoria of England had one allele for hemophilia. Most of her male descendants had the disorder, but few females had it. Why did hemophilia occur more frequently in Queen Victoria’s male descendants?
Only one copy of the X chromosome is found in cells of males, but two copies are found in cells of females
