Summary
Summary Life Sciences (Biology) - Genetics and inheritance
- Course
- Life Sciences
- Institution
- 11
Summary of genetics and inheritance
[Show more]
Seller
Follow
Content preview
GENETICS AND INHERITANCE:GENOTYPE Vs PHENOTYPE:
GENOTYPE – characteristics of the genes themselves
E.g. heterozygous / homozygous or whether the genes are recessive/ dominant
Genotype = Rr or RR
PHENOTYPES – physical characteristic of the organism
E.g. Hair colour, eye colour, hereditary diseases
Phenotype = red hair
COMPLETE DOMINANCE:
Occurs when there is dominant and recessive alleles present, the dominant gene
will always dominate the recessive therefor always appearing in the phenotypes
of the organism.
The only time that a recessive gene will be present in the phenotype in complete
dominance is when the genotype is homozygous for the recessive gene
For example B is dominant allele for brown eyes and b is the recessive allele for
blue eyes.
BB = brown eyes
Bb = brown eyes
bb = blue eyes
Mendel’s laws:
- Mendel’s law of segregation: during meiosis, allele pairs separate so that the
gametes have a single allele for each characteristic.
- Mendel’s law of dominance: in a cross of parents that are pure for contrasting
traits, only the dominant trait will appear in the phenotype. Recessive alleles
will always be masked by dominant alleles.
- Mendel’s law of independent assortment: the alleles of different genes
segregate randomly and independently of on another during gamete formation
, CO-DOMINANCE:
Occurs when two alternative dominant alleles are present in the genotype and
are fully observed in the phenotype of the organism.
A dog that has black fur mates with a dog that white fur and both black and white
alleles are dominant then their off spring will have both black and white fur
combined.
INCOMPLETE DOMINANCE:
Occurs when a dominant alleles does not quite mask the affects of9 the
recessive gene completely.
Instead both the dominant and recessive genes will combine and for a mixture of
the two.
Example a white rose is pollinated from a red rose, if there was incomplete
dominance occurring, the offspring would be pink flowers.
Complete dominance Co- dominance
Incomplete dominance
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 EFT, credit card or Stuvia-credit 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 this summary from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller athenastuviastudyguides. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy this summary for R150,00. 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 summaries for 14 years now