DNA Revolution - Inheritance of Sex
Created 2 years ago
A short explainer about the inheritance of sex for year 10 students.
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Slide 1 - DNA Revolution
- The Inheritance of sex
- Dr Eliot Attridge 2015
Slide 2 - What makes a male a male?
- There are 23 pairs of chromosomes
- One pair is the sex chromosomes
- If you get two X chromosomes, you are genetically female
- If you get an X and a Y chromosome, you will be genetically male
Slide 3 - So, is that it- XY = male?
- It is not just the carrying of an X and a Y chromosome that is important
- A lot of harm is done by assuming XY makes you male
- During development of the fetus, the Y chromosome causes the production of a male sex hormone, Androgen.
- If a person lacks Androgen receptors, the body continues developing as a female
- They will have all the sex characteristics as a female, apart from a uterus.
- They will be unable to have children
Slide 4 - Chances of boys and girls
- Assuming that a pregnancy is normal, what are the chances of getting a baby girl or boy?
- We can use Punnett squares to work out the odds:
- Male (XY)
- Female (XX)
Slide 5 - Quick question