In Gel Electrophoresis, which pieces of DNA travel furthest in the gel?
If an organism has two copies of the SAME allele, what do we call that organism? (Starts with H)
Homozygous
In guinea pigs, brown fur is dominant to white fur. What % of the offspring will be brown if you cross a Bb guinea pig with a bb guinea pig?
50%
A type of horse exhibits codominance. If you cross a homozygous white horse with a homozygous red horse, what would all the offspring look like?
Red and white spotted.
Name at least one human trait that is inherited polygenically.
height, weight, skin color, eye color, hair color
In gel electrophoresis, DNA, which is ______ (Positively/negatively) charged, moves towards the ______ (positive/negative) end of the device.
negative, positive
If an organism has two copies of a different allele, what do we call that organism? (Starts with H)
Heterozygous
In king cobras, black eyes (B) are dominant over red eyes (b). If you cross a red eyed cobra with a homozygous black eyed cobra, what genotypes can you produce?
Bb
A type of moth exhibits incomplete dominance. Two alleles control the trait - C(B) = black moths, and C(W) = white moths. What phenotypes could be produced if you cross a black moth with a grey moth?
Grey, black
What is the main difference between multiple alleles and polygenic inheritance?
Multiple alleles - more than 2 alleles on ONE gene
Polygenic inheritance - many genes interacting to produce trait
In an X-linked recessive trait, are females or males the carriers?
Always the females (carry one copy of the disease on their X-chromosome, but don't show it).
What vocab word do we use to refer to the genetic makeup of an organism?
Genotype
In horses, the allele for straight hair (H) is dominant, and the allele for curly hair (h) is recessive.
A horse breeder mates a homozygous dominant mother with a heterozygous male.
What is the percent change of getting a heterozygous offspring?
50%
A type of bird experiences incomplete dominance in it's wing color. There are two alleles - W(Y) = yellow wings, and W(B) = blue wings. What possible phenotypes does this bird species have?
A male with the blood type IAi has a child with the blood type ii. Name all possible genotypes of the other parent.
IAi, IBi, ii
0%
Colorblind father can only pass down Y to his male offspring, so he doesn't pass down X.
He passes down an X to his daughters, but it's recessive, so they are just carriers of colorblindness.
What do we call the PHYSICAL expression of a genetic trait in an organism?
Yellow color is dominant in peas, while green is recessive. You know they inherit traits through normal Mendelian genetics. What will happen if you cross a green pea and a yellow pea? a) All green b) All Yellow c) 50% green, 50% yellow d) 75% yellow, 25% green e) Impossible to tell from info given
E
A cross of grey and brown rabbits produces the following phenotypes in the offspring:
Grey
Brown
Grey + Brown
White
What type(s) of inheritance does this trait follow?
Codominance AND Multiple Alleles!
Julie has blood type O. She has one older brother with blood type B. What are TWO possible genotype combinations her parents could have?
For instance (type 1 and type 2) OR (type 3 or type 4)
IAi and IBi
or IBi or Ibi
or Ibi and ii
This pedigree is an X-linked trait.
a) Show a genotype for the first affected male in the first generation (box at the top). Use the notation X^N for a normal X chromosome, and X^n is a diseased X chromosome.
b) What is unusual about this X-linked trait?
a) X^n Y
b) It's dominant!
What is the definition of an allele?
A variation on a gene
You are breeding bean plants in the garden, which come in two varieties, purple and green. You know they inherit traits through normal Mendelian genetics. You breed two purple plants together for over 10 generations and always produce purple plants. What can you conclude? a) Purple is the dominant color in beans b) Purple is the recessive color in beans c) Need more information to be sure
C
Skin color is inherited by incomplete dominance in a type of lizards. The allele S(Y) produces yellow skin, and the allele S(B) produces blue skin. There is a third allele, S(R), that produces red skin and is recessive to both others. You cross a S(Y)S(B) lizard with a red-skinned lizard. 1. What was the phenotype of the S(Y)S(B) lizard?
2. List the percent chance of getting each phenotype.
1. Green
2. 50% Yellow, 50% Blue
Think back to our class example for polygenic inheritance, our twins. Remember, uppercase alleles (A, B, C) denote MORE melanin and darker skin. Lowercase alleles (a, b, c) denote LESS melanin and lighter skin.
Let's say the mom's genotype is Aabbcc.
Let's say the dad's genotype is AABbCc.
Using these genotypes, what is the MOST likely genotype of the darker-skinned twin?
AABbCc.
must inherit lowercase b and lowercase c from mom (that's all she has to give). But since she has darker skin, she inherits uppercase A from both, and uppercase B and C from dad, leading to 4 melanin producing alleles and 2 non-melanin producing alleles.