odd one out.... fertilisation lesson learning outcomes: increasing difficulty define the term random...

Odd one out...

Fertilisation

• Lesson Learning Outcomes:

Increasing Difficulty

What is independent assortment of chromosomes?

Define the term

random fertilisation

Describe how sexual

reproduction leads to

variation.

Explain why different offspring

from the same parents look different.

Harry Potter and the

Recessive Allele

How Are Wizards Made?

How Are Wizards Made?

• Being a wizard or a muggle is all decided by genetics

• All humans including wizards receive one allele from each parent

How Are Wizards Made?

• The allele for wizarding ability is

m

• Wizards have the alleles mm

How Are Wizards Made?

• The allele for muggleness is M

• Muggles have the alleles Mm or

MM

• M is dominant to m so you can only be a wizard if you have no M allele

The Malfoys

Lucius Malfoy (mm)

Narcissa Malfoy (mm)

Draco Malfoy( )

The Malfoys are a ‘pure blood’ family

All their ancestors are wizards so they must have the alleles mm

mmWhat alleles will Draco have inherited?

Lily Potter (mm)

James Potter (mm)

Harry Potter (WW)

Both Harry’s parents had magical ability so they must both have been mm

They passed these alleles on to Harry

The Potters

mm

The Weasleys are pure blood wizards so they all have the alleles mm

Hermione is a powerful witch so she must be mm.

Both her parents are muggles, so how can this be?

Mm Mm

mm

Mum Dad

Hermiones parents are muggles because they both have the dominant muggle allele (M), but they also both have the recessive wizard allele (m) which is the one that has been passed on to Hermione in this case

Tom Riddle is a ‘half blood’.

His mother was a witch (mm) and his father was a muggle

What alleles must his father have had?

mm Mm

mm

MumDad

Filch is a ‘squib’

Both his parents are mm so he should be too because he can’t get an M allele from either parent but he can’t do any magic

This means he has a mutation so his wizarding powers don’t work or the man he thinks is his father isn’t really and his mother had an affair with a muggle!

What wizarding alleles would Ron and Hermione’s children have?

Ron (mm)

Hermione (mm)

Children

( )mm

Ron

m m

Hermione

m

m

Their children could only get the m allele from both parents so they would all be wizards

mm mm

mm mm

What wizarding alleles would Ginny and Dudley’s children have?

If Dudley is Mm

Ginny mm

Dudley Mm

Children

WW or mMmM mm

Dudley

m M

Ginny

m

m

Half of their children would be likely to get the m allele from both parents so they would be wizards

The other half would be likely to get an M allele from Dudley and would be muggles

m m

m m

m M

m M

What wizarding alleles would Ginny and Dudley’s children have?

If Dudley is MM

Ginny mm

Dudley MM

Children

WMm M

Dudley

M M

Ginnym WM WM

m WM WM

Their children would get the m allele from Ginny and the M allele from Dudley so they would all be muggles

m M m M

m M m M

What wizarding alleles would you

expect Hermione’s

brothers and sisters to have?

Mr Granger

m M

Mrs Granger

m WW WM

M WM MM

The Granger’s children have a 1 in 4 chance of getting m alleles from both parents (mm) and having magical ability

m M

m M

m m

M M

They also have a 3 in 4 chance of getting at least one M allele (Mm or MM) and being a muggle

They also have a 2 in 4 (50%) chance of being a ‘carrier’ of the recessive wizard allele (Mm) even though they themselves are muggles

Reebops• Reebops are small worm like creatures that

live in classrooms all over the world

Reebops

• They are little worm-like creatures that have three segments on their bodies and six legs.

• Instead of having 23 pairs of chromosomes like humans they have 8 pairs of chromosomes.

• You are going to create your own reebops.

Reebops

• Mammy Reebop • Daddy Reebop

• In your pair one person is the mammy reebop (pink chromosomes) and one person is the daddy reebop (blue chromosomes)

Reebops• The features of reebops are controlled by a

number of different alleles• In your pair you have each been given a set of

reebop chromosomes (the pink ones are for the mother and the blue are for the father)

• Put both sets of chromosomes letter side face down on the table.

Sex Cells• Start by making ova:• Take it in turns to pick one chromosome from

each pair of the pink chromosomes• You have each produced an ovum• Then repeat with the blue pairs to produce

sperm

Reebops• Now each person should have an ovum and a

sperm• Mix the chromosomes up to represent fertilisation• Turn the chromosomes over• Use the chromosomes as instructions to make your

own reebop.• When you are done take a picture of it using your

phone or your friends if you haven’t got one and email it to me:

• Louise.maughan@ntlp.org.uk

Musical TOUR

Take a tour of the reebops around the room, make a list of similarities and differences to your reebop

Can you explain why

they all look diff erent?

Genetic Cross snowballing

• Write a problem for someone else (they must have to solve it using a genetic cross diagram).

• Don’t forget to say which characteristic is dominant and which one is recessive