Class Notes (921,234)
CA (542,480)
UTSG (45,900)
HMB265H1 (253)
Lecture

Notes taken during lecture

6 Pages
106 Views

Department
Human Biology
Course Code
HMB265H1
Professor
Stephen Wright

This preview shows pages 1-2. Sign up to view the full 6 pages of the document.
LECTURE 14 March 3rd
Quantitative traits = complex traits
Variation in average differences in genotypes between individuals AND environmental
variation that gives phenotypic variation
Environmental variation because of food, climate, illnesses, etc.
Maristic traits class of discrete traits
Discrete traits either or traits; single-gene traits
MARISTIC TRAITS:
Whole-number range of values possibilities are not infinite
Ex. number of progeny
Additive inheritance and incomplete dominance
Additive gene action in heterozygote, exactly intermediate of the two
homozygotes
oThis occurs with additive effects
Incomplete dominance is example of additive gene action
oHeterozygote has trait value or state that is intermediate quantitatively
between the two homozygous classes but NOT EXACTLY
INTERMEDIATE
oThis occurs because of environmental variation
Mutations in few genes cause familial hypercolesteremia
Still single-gene disease/disorder
Because any one of the many genes is mutated can result in this
Heterozygotes
Blurring of lines
oGenotypically heterozygote but phenotypically homozygous can result
because of environmental influence
TODAYs lecture quantitative trait analysis
Phenotype = E and genotype
How much is due to genetic variation?
Broad sense extend of phenotypic variation that is attributed to genetic variation, all
types of genetic variation
Can be quantified by Hsquared (representing broad sense)
Vp = Vg + Ve
Values range between 0 and 1
oThere is no env effect if 1 all variation caused by genetic effects
www.notesolution.com
oMinimum is 0 env effect is 100%
BSH tells us
oHigh values suggest that the genotype is important in determining
whether this quantitative trait arises due to the segregation of particular
or specific alleles
oImportant in attributing whether this quantitive trait (hair colour,
weight)
oBUT NOT PREDICTIVE
Cant take Hsquared and predict what the progeny will look like
based on the phenotype of the parents
Hsquared for some humans
Height pretty hight
oGenetic component
Heart rate at the middle gen and env variation equal
What does BSH tell us?
High phenotype is likely to be attributed to its genotype within that family
oCannot extrapolate to other families, to other populations
oValues are specific to the family or the population
Why is BSH not predictive?
Predicting genotype and phenotype of offspring is important, especially to plant
and animal breeders using artificial selection to enhance traits
oThey dont use BSH
Look at the equation
oGenetic variation types include additive effects, dominance effects,
epistatic effects
I stands for interacting
Epistatis occurs when two genes or proteins are INTERACTING,
giving you another phenotype OR one locus masks effect of other
locus
Genetic variation can be divided into 3 types ***
To answer, examine V due to dominance effects
oCannot predict progeny accurately
oPlant breeders want to optimize specific traits
oDOMINANCE EFFECTS ARE NOT PREDICTIVE
oAs for epistatic variation,
Recessive epistatis R1 masking R2 allele
Every generation, new dominance and epistatic relationships are
formed each generation
So they are not predictive
Passing on genotype, not alleles these new combinations occur
generation to generation
oLeft with additive variation
www.notesolution.com

Loved by over 2.2 million students

Over 90% improved by at least one letter grade.

Leah — University of Toronto

OneClass has been such a huge help in my studies at UofT especially since I am a transfer student. OneClass is the study buddy I never had before and definitely gives me the extra push to get from a B to an A!

Leah — University of Toronto
Saarim — University of Michigan

Balancing social life With academics can be difficult, that is why I'm so glad that OneClass is out there where I can find the top notes for all of my classes. Now I can be the all-star student I want to be.

Saarim — University of Michigan
Jenna — University of Wisconsin

As a college student living on a college budget, I love how easy it is to earn gift cards just by submitting my notes.

Jenna — University of Wisconsin
Anne — University of California

OneClass has allowed me to catch up with my most difficult course! #lifesaver

Anne — University of California
Description
rd LECTURE 14 March 3 Quantitative traits = complex traits Variation in average differences in genotypes between individuals AND environmental variation that gives phenotypic variation Environmental variation because of food, climate, illnesses, etc. Maristic traits class of discrete traits Discrete traits either or traits; single-gene traits MARISTIC TRAITS: Whole-number range of values possibilities are not infinite Ex. number of progeny Additive inheritance and incomplete dominance Additive gene action in heterozygote, exactly intermediate of the two homozygotes o This occurs with additive effects Incomplete dominance is example of additive gene action o Heterozygote has trait value or state that is intermediate quantitatively between the two homozygous classes but NOT EXACTLY INTERMEDIATE o This occurs because of environmental variation Mutations in few genes cause familial hypercolesteremia Still single-gene diseasedisorder Because any one of the many genes is mutated can result in this Heterozygotes Blurring of lines o Genotypically heterozygote but phenotypically homozygous can result because of environmental influence TODAYs lecture quantitative trait analysis Phenotype = E and genotype How much is due to genetic variation? Broad sense extend of phenotypic variation that is attributed to genetic variation, all types of genetic variation Can be quantified by Hsquared (representing broad sense) Vp = Vg + Ve Values range between 0 and 1 o There is no env effect if 1 all variation caused by genetic effects www.notesolution.com
More Less
Unlock Document


Only pages 1-2 are available for preview. Some parts have been intentionally blurred.

Unlock Document
You're Reading a Preview

Unlock to view full version

Unlock Document

Log In


OR

Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit