Lecture 11 Flashcards
So far we learned about the 2 laws from Mendel, name them
The Law of Segregation and The Law of Independent Assortment
Which Law is connected to monohybrid and dihybrid crosses?
Segregation = Mono (dom/rec alleles)
Ind. Assortment = Di (2 separate genes)
Name all 10 aspects BEYOND Mendel
a) Incomplete Dominance
b) Codominance
c) Multiple Alleles
d) Epistasis
e) Pleiotropy
f) Polygenic Inheritance
g) Sex-linked Inheritance
h) Variation in Chromosome Number
i) Variations in Chromosome Structure
j) Genes and the Environment
What is an Incomplete Dominance?
it’s a blending of traits
(neither allele is dominant); instead, they blend together
So what does Incomplete Dominance mean (think of the genotype)?
The heterozygous form is intermediate b/w that of the 2 homozygous forms
Let’s use an example to solidify our comprehension: what happens if you crossbreed a red flower and a white flower…
In an incomplete dominance, you might get a pink flower.
The pink flower is neither fully red nor fully white. It’s somewhere in between, showing a blend of both traits.
What is Codominance?
when both traits are equally expressed
So what does Codominance mean (think of the genotype)?
heterozygous simultaneously expresses the phenotype of both homozygotes
For example, let’s talk about cattle and horses. Imagine there are two coat colors: red and white. What would the result be in terms of co-dominance?
In codominance, neither color is dominant over the other.
= The offspring could be a mix of both colors. This mix shows up as patches of red and white all over the body.
What are these types of horses called?
roan
What involves 3 alleles?
ABO
However, why can an individual only have 2 regardless of how many alleles exist?
because you only have 2 pairs of homologous chromosomes for each of your 23 chromosomes
What are the 3 alleles for ABO?
I^A (type A), I^B (type B), i (type O)
What would be the alleles of a father AB and a hetero A Mother?
Father: I^A I^B
Mother: I^A i
Make a Punnett square out of this information, what are the possible offspring with the phenotypes and genotypes
check p. 7 for answers
Type A
Type AB
Type A
Type B
+ Do Baby Mix Up problem (p.8-9)
What is called the interaction between genes that influences a phenotype?
Epistasis
Define more epistasis:
The presence of certain alleles of one locus can PREVENT OR MASK the expression of alleles of a different locus
Definition of Pleiotropy: A single gene may affect ______ ________?
multiple phenotypes
When does Pleiotropy occur?
when different cell types use a gene product or have a signaling function on various targets
What are 2 main/common examples?
cystic fibrosis & sickle cell anemia
What is cystic fibrosis?
defective protein found in the plasma membrane of lungs, intestines, pancreas, liver, sweat glands
What is sickle cell anemia?
defective protein in red blood cells
leads to multiple symptoms (heart failure, jaundice, pain, etc.)
