Class Notes (903,845)
CA (538,103)
Ryerson (30,336)
BLG (541)
BLG 144 (97)
Ron Babin (38)
Lecture

inheritence

2 Pages
86 Views

Department
Biology
Course Code
BLG 144
Professor
Ron Babin

This preview shows half of the first page. Sign up to view the full 2 pages of the document.
Stages of Meiosis
Interphase
DNA replicates → Identical sister chromatids form
Meiosis I
Meiosis II (same as mitosis)
Prophase
//Spindle forms
Nuclear envelope disappears
- Chromosomes shorten/thicken/condense
- Form bivalents/tetrads
- Crossing-over of homologous pairs
//Spindle forms
//Nuclear envelope disappears
Metaphase
//Spindle complete
- Bivalents at equator
- Join to spindle (fibres) via centromere
//Spindle complete
- Chromosomes at equator
Anaphase
//Cytokinesis begin
Random segregation of homologues
- Intact centromeres
- Two chromatids on one chromosome
//Cytokinesis begins
Random segregation of chromatids
- Chromatids are pulled to opposite poles
- Centromeres divide
Telophase
//Spindle disappears
//Nuclear envelope reforms
- 2 haploid cells
- Chromosomes still duplicated
//Spindle disappears
//Nuclear envelope reforms
- 4 haploid daughter cells
Principles of Mendelian Inheritance
Mendel's 1st Law of Segregation (Anaphase I and II)
o During gamete formation, allele pairs (Gg) of one gene separate (G)(g)
o Thus, only one of the alleles of one gene is present in a single gamete
o Monohybrid inheritance (single gene - 3:1 ratio)
o Recessive alleles can cause genetic disorders (e.g. cystic fibrosis)
Mendel's 2nd Law of Independent Assortment (Anaphase I and II)
o Alleles for one gene segregate independently with the alleles of another gene
(GgBb)
o Two genes for each characteristic segregate during gamete production
(GB)(gb)(Gb)(gB)
o Independent assortment means either G / g can go with either of B / b
o Meiosis separates alleles / homologous chromosomes
o Dihybrid inheritance (two genes - 9:3:3:1 ratio) → occurs at different loci
Multiple Alleles
Human ABO group is controlled by the immunoglobulin gene I
o The immunoglobulin gene has 3 alleles IA, IB, I0
o These alleles code for antigen A, B, neither A/B, respectively
Only 2 alleles can be present in a diploid cell → IAIB is codominant, I0 recessive

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
Stages of Meiosis Interphase DNA replicates → Identical sister chromatids form Meiosis I Meiosis II (same as mitosis) Prophase //Spindle forms //Spindle forms Nuclear envelope disappears //Nuclear envelope disappears - Chromosomes shorten/thicken/condense - Form bivalents/tetrads - Crossing-over of homologous pairs Metaphase//Spindle complete //Spindle complete - Bivalents at equator - Chromosomes at equator - Join to spindle (fibres) via centromere Anaphase //Cytokinesis begin //Cytokinesis begins Random segregation of homologues Random segregation of chromatids - Intact centromeres - Chromatids are pulled to opposite poles - Two chromatids on one chromosome - Centromeres divide Telophase //Spindle disappears //Spindle disappears //Nuclear envelope reforms //Nuclear envelope reforms - 2 haploid cells - 4 haploid daughter cells - Chromosomes still duplicated Principles of Mendelian Inheritance  Mendel's 1st Law of Segregation (Anaphase I and II) o During gamete formation, allele pairs (Gg) of one gene separate (G)(g) o Thus, only one of the alleles of one gene is present in a single gamete o Monohybrid inheritance (single gene - 3:1 ratio) o Recessive alleles can cause genetic disorders (e.g. cystic fibrosis)  Mendel's 2nd Law of Independent Assortment (Anaphase I and II) o Alleles for one gene segregate independently with the alleles of another gene (GgBb) o Two genes for each characteristic segregate during gamete production (GB)(gb)(Gb)(gB) o Independent assortment means either G / g can go with either of B / b o Meiosis separates alleles / h
More Less
Unlock Document


Only half of the first page 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