Sex Linkage

 SEX LINKED GENES

The sex chromosomes are XX and XY in humans. Some alleles are located on the X chromosome. But very few on the Y chromosome.  Remember that people who are  females have the genotype XX and people who are males have XY.

The Y chromosome carries very little information, only enough to influence the embryo on the path towards male primary and secondary characteristics.

Meanwhile, many RECESSIVE ALLELES are located on the X chromosome, including
1. hemophilia, the inability to clot blood
2. colourblindness inability to tell the difference between red and green colour
3.  baldness

These characteristics are far more common in malea than females because males have only one X. And if that X contains the recessive allele, they will show the phenotype.  Meanwhile, females may have the recessive and their dominant genes on their other X will protect them.  For example

An example of using a punnet square to calculate probability is here:

Some things to note about sex linkage:  Signs of sex linked alleles are:
1. more males get the phenotype, but females can be carriers
2.  males can inherit from mother but not father (because males get their X from mom)
3.  females have an extra X and this protects them.  Females must be homozygous to show the sex linked phenotype.
Further reading on sex linkage here http://learn.genetics.utah.edu/content/pigeons/sexlinkage/

FYI if you were born a male and you want to know if you're colourblind:  Test yourself here: But careful, if you are a genetically male, you might find out you are colour blind!  Apparently most people find out they are colourblind from their science teacher !  

https://colormax.org/color-blind-test/

Basic practice worksheet going over main concepts

Worksheet B

What colour is that dress?

 

There is a very interesting dress. It has caused major arguments!  This dress causes your cells in your retinas to perceive it to be certain colours depending on the state of your retinas. Of course your genes determine what your retinas are like...but also your retinas change over time too!  

Your perception is also based on whether you think this dress is in shadow or light...Try this, 

 I would like you to ask  20 people you know "What colours do you see on this dress:  Is it :  

A. GOLD AND WHITE 

B.  BLACK AND BLUE

C.  GOLD AND BLUE

D.  NONE OF THE ABOVE...THEN what colour is it?  

What are the characteristics of the people who are more likely to say that it is any of the choices above?   

Remember you can poll people without meeting face to face. Ask a variety of people including old, young, male, female...put your results on a table and hypothesize why people see different colours

  

Pon Farr

VULCANS are a logical species where emotions play no role in producing offspring.  All offspring are the result of in vitro fertilization. They form no attachments with their mates. 

Purpose:  To have hypothetical offspring with  1 or 2 other individuals

In the class and calculate the probability of certain traits using a punnet

Square.  

Next, you will perform a Vulcan mating ritual (pon farr) where

you RANDOMLY PICK AN ALLELE CARD from the other person and they randomly pick

one of your allele CARDS FOR ANY PARTICULAR TRAIT. 

Then observe the traits of your offspring.  Have 2 kids per mate or have 4 kids with one other mate

Keep track of the genotype of each kid.  By the end of the activity, you will have 4 kids

Method:

Write down your phenotype for the following characteristics:

Earlobe attachment EE, or Ee.    unattached  ee

Tongue rolling TT or Tt              no tongue rolling tt

Cleft chin   CC or Cc                  no cleft cc

Widow’s peak WW or Ww.          straight hairline ww                    

Natural curl. NN.         straight hair nn.          wavy Nn       

Dimples DD or Dd            no dimples. dd

Righty RR   or Rr.          lefty rr

Freckles FF  or Ff           no freckles ff

internal ovaries  XX       internal testes XY

METHOD 

For each trait,  make the genotype as alleles on two small pieces of paper.

 Write your phenotypes now:

For each mate you have draw the punnet squares  representing

 each trait and

calculate the Probability of each trait.

Mate 1’s  genotype:_Ff WW tt nn rr dd cc  Ee__XX_________________

Punnet squares: indicate probability

Actual genotypes of the offspring. Draw a cartoon of each your kids. Name them

Offspring :

1.ff Ww Tt  Dd Cc EE rr

2.

3.

4.

Introductory lesson on Genetics: How to write punnet squares

 Watch the introduction to Genetics video and make notes on it. You may use the notes organizer I provided in class called "The analogy of shoes". Please make a correction on the student notes.  Where it says "boy" cross it out and put XY .  Where it says girl, cross that out and put XX.  Note that XY individuals produce sperm and XX individuals produce eggs.  

The term "boy" and "girl" refers to gender identity and this identity can be from an individual who has XX or XY.  

Onion lab

 You will examine live onion cells and stain them for the nucleus using 99% ethanol (the higher concentration the better) and food dye 

Microscopes part 1

PART 1: 

Look at the following specimens under the microscope: (5)

make a prepared slide for a light microscope and upload your picture on the Class Observations section of TEAMS: ( 5 marks) 

moss

blade of grass

paper towel

hair.

Draw these objects under low and medium power.  (10 marks)

PART 2: HOW TO MEASURE FIELD OF VIEW and CALCULATE FIELD OF VIEW

 Measure the diameter of the field of view of the low view of the microscope.

Write it down in mm.  You can convert this to microns by x1000

Now calculate the diametre of the field of view.



The formula we use:

dFOV 2    =      dFOV 1    x    magnification of 1
                         ___________________________
                                          magnification of 2

or

dFOV medium =   dFOVlow   x low magnification
                              _________________________
                                           magnification of medium


dFOV high =  dFOVlow   x low magnification
                       _________________________
                                 magnification of high

Lab 2 :  demonstrate that you can estimate the size of an object.    10 marks

Draw any object under low, medium and high and indicate the diametre of the field of view and also the length of something under the microscope. 

1. Draw the ruler under lowest power and tell me the diameter of the field of view.

2.  Draw a specimen under low, medium and high . Use a petri dish to draw the circle 

3.  Calculate the diameter for

a.  MEDIUM

b.  HIGH

4. Use the diameter of the field of view to measure the SIZE of the object that you drew.  

Show your work 

Watson and Crick and Franklin

 

Here is another video from youtube which explains these concepts in more detail.





Assignment - 15 points

SUMMARIZE THE MAIN POINTS OF DNA NOTES 10 points

A. Summarize the main points of the DNA notes AND the DNA slide show in a Cartoon Format and make a clear photo of this cartoon.  upload your assignment in Microsoft Teams.   Include the details about Watson and Crick and Franklin.

EVALUATION rubric
10 points:  You included all the main points in a colourful, creative format which is written in ink and coloured.  You used humour and creativity and your assignment stands out for showing an understanding of the key points

8-9 :  you include all the main points and you show excellence and creativity. your assignment is in colour and inked

5-7 :  you include most of the main points and your assignment is handed in. It is a good start and  You needed more time to finish this.

2-4:  you handed something in that was not quite complete, although it is a pretty good start

You may do Assignment 3 Aas a poem that rhymes if you don't want to draw.

3B.  take a picture of  your drawing of this worksheet filled out: You may redraw it or edit it in Paint.
5 points