x - linked genes

  SEX LINKED GENES

In the following post, I will refer to the term  "male" and "female".  This refers to people with male sex organs or people with female sex organs.  People with these organs can identify with a diverse range of gender such as:

Man, woman, nonbinary. This gender identify is not presumed by the presence of male or female sex organs

They might also identify as

LGBTQ2S++

The following descriptions are biological descriptions refer to 

male= has male sex organs like testes, producing male gametes such as sperm

female= has female sex organs like ovaries, producing female gametes such as  eggs. 

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 people with male sex organs  than people with female sex organs because  people with male organs have only one X. And if that X contains the recessive allele, they will show the phenotype.  Meanwhile,people with  female organs 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 genotypic males get the phenotype, but genotypic females can be carriers
2.  males can inherit from mother but not father (because males get their X from mom)
3.  genotypic 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 !  
http://colorvisiontesting.com/home.html

Basic practice worksheet going over main concepts

Worksheet B

That Dress! and the science of perception

 

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

  

Introduction to Genetics

 Watch my introduction to Genetics video and make notes on it. 

Intro to Genetics ASSIGNMENT /40 marks 
Answer these questions on this worksheet  on A SEPARATE PAPER  in ink, or TYPED. ANSWER IN COMPLETE SENTENCES.  

In addition, write down your phenotype for the following characteristics 

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

Clover Genetic Variation

  We know that plants are important to the ecosystem because they photosynthesize. Did you know that some plants are legumes and these are special because they have ROOT NODULES which are nitrogen fixers.  These root nodules are little rooms where Rhizobium bacteria convert nitrogen gas into ammonium and then Nitrobacter bacterium in the soil  converts ammonium into nitrates. Plants can absorb nitrates to make plant protein.  When those plants are eaten by animals, then animals use the nitrogen to make animal protein.  You can say that all the protein on your body (muscles, enzymes, hair, fingernail etc) was built from nitrogen which was fixed by Rhizobium at some point in time.  

ASSIGNMENT:  10 points

Only certain plants contain these root nodules...amongst them are  bean plants and clover plants.   Look at the morphology of clover plants below.  Look on our school grounds  and find AS MANY DIFFERENT GENETIC VARIETIES as you can.  Upload your clover pic  on a doc or ppt and hand in. 

This picture is from research done by Tashiro et al on the genetics of clover plants.  https://www.researchgate.net/publication/250119450_Leaf_Trait_Coloration_in_White_Clover_and_Molecular_Mapping_of_the_Red_Midrib_and_Leaflet_Number_Traits

CREATE A CHART SHOWING

1. Your pictures of the clovers or clover patch

2.  The numbers of EACH TYPE of clover 

3.   Why is it important to keep a species inventory of plants such as clover in an ecosystem?