Class Notes (905,911)
CA (538,524)
UTSG (45,722)
HMB265H1 (252)
Lecture

Notes taken during lecture

5 Pages
137 Views

Department
Human Biology
Course Code
HMB265H1
Professor
Stephen Wright

This preview shows pages 1-2. Sign up to view the full 5 pages of the document.
LECTURE 22
Final Exam:
April 12th from 2-4pm
Both sections
20-25% based on first semester
Rest based on second semester
Tutorial
Quiz epigenetics and genetics
oLook over calculations for odds ratios and lod ratios
oQuantitative genetics calculations
Regulated gene expression
All start with same types of cells, stem cells, containing same amount of genes,
DNA
Genes regulated by other factors and proteins within genome
Model organisms used to study development
oZebrafish
oNematode c elegans
oArabidopsis
oMouse
oFruit flies
oUsed to
Small size so easily manipulated
Look at flies and mice to drive development in humans
Pathways and genetic mechanisms conserved
What occurs in flies, occur in humans
Genomes sequenced so can find genes with mutant
phenotypes
All living forms are related
Fly
Loss of function of eyeless gene in drosophila = > no eye or small eye forming
Pax-6 gene is homolog of eyeless
Analog in humans called Aniridia
MUTATIONS
oNo functional copies of aniridia eyes embryos have no eye formation,
lethality in utero
Homozygous loss of function leads to embryonic lethality
oHeterozygote lack one or two irises
One wildtype only
Knockout reverse genetics
www.notesolution.com
To see what genes are important in what pathways? What defects result? Genes
important for what?
Forward geneticsmutagenize model organisms
oCross mutant mice with wildtype mice to perform phenotypic analysis
Drosophila so important
oBest genetic model organism THUS best model to study function of genes
in development
oEmbryo to adult = 10-11 days at 23 degrees C
oGenes positioning relationship btw axis conserved among species
Correct formation of axises in embryo lead to normal adult fly
1995 Nobel prize for discoveries concerning early development of drosophila
embryos
Found the genes controlling axis and that they were conserved
Different classes of drosohpila genes important for patterning of embryo
Anterior posterior pattern development focused today
oFirst class is maternal effect genes
Maternal effect mRNAs deposited in early embryo by mother
These genes direct formation of anterior, posterior axis in fly
Genotype of mother important
If mother has at least one wildtype copy of maternal effect
gene, then will have functional maternal affect protein
If lack protein, then embryo will lack functional maternal
affect protein, resulting in mutant embryo
Father does not matter true for many species, including
humans
Mothers genes that set up axis
oMust have at least one wildtype copy in order to have
normal maternal affect proteins
Present in concentration gradient
Bicoid = maternal effect gene, deposited and localized to
anterior portion of drosophila embryo
Gradient
oEmbryo synsinitia
Nuclear division without cytoplasmic division
One embryo has many nuclei, but not cellular
division
So easy for RNAs deposited to diffuse from
one end to other
If bicoid at anterior end, see gradient of
expression from antieror to posterior
Very little expression when get past embryo
Embryos lacking bicoid protein because
mother had no functional copies of gene
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
LECTURE 22 Final Exam: April 12 from 2-4pm Both sections 20-25% based on first semester Rest based on second semester Tutorial Quiz – epigenetics and genetics o Look over calculations for odds ratios and lod ratios o Quantitative genetics calculations Regulated gene expression All start with same types of cells, stem cells, containing same amount of genes, DNA Genes regulated by other factors and proteins within genome Model organisms used to study development o Zebrafish o Nematode c elegans o Arabidopsis o Mouse o Fruit flies o Used to Small size so easily manipulated Look at flies and mice to drive development in humans • Pathways and genetic mechanisms conserved • What occurs in flies, occur in humans • Genomes sequenced so can find genes with mutant phenotypes All living forms are related Fly Loss of function of eyeless gene in drosophila = > no eye or small eye forming Pax-6 gene is homolog of eyeless Analog in humans called Aniridia MUTATIONS o No functional copies of aniridia eyes – embryos have no eye formation, lethality in utero Homozygous loss of function leads to embryonic lethality o Heterozygote – lack one or two irises One wildtype only Knockout – reverse genetics www.notesolution.com To see what genes are important in what pathways? What defects result? Genes important for what? Forward genetics…mutagenize model organisms o Cross mutant mice with wildtype mice to perform phenotypic analysis Drosophila so important o Best genetic model organism THUS best model to study function of genes in development o Embryo to adult = 10-11 days at 23 degrees C o Genes positioning relationship btw axis conserved among species Correct formation of axises in embryo lead to normal adult fly 1995 – Nobel prize for discoveries concerning early development of drosophila embryos Found the genes controlling axis and that they were conserved Different classes of drosohpila genes important for patterning of embryo Anterior posterior pattern development focused today o First class is maternal effect genes Maternal effect mRNAs deposited in early embryo by mother These genes direct formation of anterior, posterior axis in fly Genotype of mother important • If mother has at least one wildtype copy of maternal effect gene, then will have functional maternal affect protein • If lack protein, then embryo will lack functional maternal affect protein, resulting in mutant embryo • Father does not matter – true for many species, including humans • Mother’s genes that set up axis o Must have at least one wildtype copy in order to have normal maternal affect proteins Present in concentration gradient • Bicoid = maternal effect gene, deposited and localized to anterior portion of drosophila embryo • Gradient o Embryo synsinitia Nuclear division without cytoplasmic division One embryo has many nuclei, but not cellular division So easy for RNAs deposited to diffuse from one end to other If bicoid at anterior end, see gradient of expression from antieror to posterior Very little expression when get past embryo Embryos lacking bicoid protein because mother had no functional copies of gene www.notesolution.com • If responsible for antieror position then embryos lack antieor portion Second, third, and fourth types are zygotic genes • Encode zygotically active proteins responsible for segmentation seen within embryo • Second class are gap genes o Affect formation of continous segment in embryo o Lack expression – see broad regions of embryo or larva being deleted o Kruppel Expressed in yellow, without it then result in short lethal embryo Third class called pair rule class • Act at double segment • Present at specific position in each pair of segments • The final embryo and la
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