Summary
Summary OCR A-Level Biology 6.2.8 Epistasis
Revision summary of key knowledge from OCR A-Level Biology 6.2.8 Epistasis.
[Show more]
Connected book
Book Title:
Author(s):
- Edition:
- ISBN:
- Edition:
Seller
Follow
Content preview
EpistasisDominant Epistasis
Presence of a dominant epistatic gene prevents the expression of a hypostatic gene,
regardless of its dominance
Dominant epistatic gene in Labradors means that black pigment is produced which
overrides the pigment produced by the hypostatic gene, leading to black fur
12:3:1 Example:
o A is a dominant epistatic gene coding for no pigment
o B is a hypostatic gene coding for yellow pigment
o b is a hypostatic gene coding for green pigment
Parent Phenotype Double Heterozygous x Double Heterozygous
Parent Genotype AaBb x AaBb
Parent Gametes AB Ab aB ab AB Ab aB ab
Dihybrid Cross AB Ab aB ab
A AAB AAB
AABB AaBb
B b b
A AAb
AABb AaBb Aabb
b b
AAB
aB AaBb aaBB aaBb
b
ab AaBb Aabb aaBb aabb
Ratio White = 12
Yellow = 3
Green = 1
13:3 Example:
o A is a dominant recessive gene coding for no pigment
o B is a hypostatic gene coding for brown pigment
Parent Phenotype Double Heterozygous x Double Heterozygous
Parent Genotype AaBb x AaBb
Parent Gametes AB Ab aB ab AB Ab aB ab
Dihybrid Cross AB Ab aB ab
A AAB
AABB AaBb AABb
B b
Ab AABb AAbb AaBb Aabb
AAB
aB AaBb aaBB aaBb
b
ab AaBb Aabb aaBb aabb
Ratio White = 13
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller izzylewington04. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £2.99. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
64438 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy revision notes and other study material for 14 years now