Meiosis in males and females: Differences and consequences

thereof. Active Lesson

Developed by the following at HHMI Summer Institute 2012

Philip Farabaugh (UMBC), Benedict Kolber (Duquesne University), Mary Konsolaki (Rutgers), Joseph

McCormick (Duquesne University), Karen Schindler (Rutgers), Cynthia Wagner (UMBC), Mike Verzi

(Rutgers) This is the instructional Powerpoint which contains instructions

plus the teachable Powerpoint.See the “Active Lesson Presentation Ready” file for a ready-to-go

Powerpoint for your class.

Intended Audience

•Introductory Biology or Genetics •100-300 level

•1st, 2nd, 3rd year students

•Biology majors

•Prerequisites: precalc, gen chem

Prior Knowledge/Lessons

•Stages of meiosis•Compare/contrast

mitosis/meiosis•Recombination•Non-disjunction in the context

of recombination•Warm-up reading of male vs.

female meiosis (from textbook)

Learning Goal

•Understand meiosis

Outcomes

The students should be able to:•1. Describe differences between meiosis in females and males.

•2. Explain the differences in the rate of non-disjunction between females and males

The next slide is the start of the actual presentation. Additional instructor notes can be found below in Powerpoint notes area.

Note: Suggested animations have already been added in the Powerpoint.

Female vs. Male Meiosis

•What you have - Strips describing steps of meiosis.

•What you need to do - Place the strips in order from first to last. Do this for both the males and females.

Let’s go through the strips of female meiosis.

Meiosis initiated in fetal development

One functional germ cell

Resumption upon puberty

Arrested at metaphase of

meiosis II

Asymmetric cell division

Arrested in prophase of meiosis I

Let’s go through the strips of male meiosis.

Meiosis initiated in puberty

Symmetric cell division

4 functional germ cells

Symmetric cell division

Meiosis proceeds uninterrupted

Let’s now compare males and females on a time-line.

Females MalesFetal

Puberty

Meiosis initiated

Arr

es

t

Resumption of meiosis

Meiosis initiated

Asymmetric division

Symmetric division

Asymmetric division

Symmetric division

Cycl

ical

Con

tinu

ou

s

8Menopause

Case Study

This graph shows the rates of trisomy in females and

males.

Hecht, C. A. and Hook, E. B. 1996.

Using your clicker, select the best biological choice of sperm donor that the couple should use.

A. 50 year old maleB. 35 year-old maleC. Either maleD. Younger

anonymous male donor

Space for clicker graph

Defects in meiosis affect human reproduction – 1

minute essay •Devise a plausible cellular process

that explains why there is an increase of trisomies in females as they age compared to males.

•Every student should describe their mechanism in a 1min essay and submit at the end of class (please put your name on the card).

Take-home assignment looking at new data

showing that paternal age affects schizophrenia.•On your own for next class:•Read the following•Malaspina  D;  Harlap  S;  Fennig  S; 

Heiman  D;  Nahon  D;  Feldman  D;  Susser  ES:  Advancing paternal age and the risk of schizophrenia.  Arch Gen Psychiatry   2001; 58:361—367.

•Talk about whether these new data would affect Sheldon and Pete’s decision on a sperm donor.

Additional Reading

•Hunt & Hassold. Female Meiosis: Coming unglued with age. Current Bio 20(17). 2010

•That’s it!!!!!