1. Chapter 11
Heredity and genetics

2. Heredity Heredity is the passing of traits from parent to offspring.
Eye color, nose shape, and many other physical features are some of the traits that are inherited from parents.

3. Allele
The different forms of a trait that a gene may have are called alleles.
For example—if one of your parents has brown eyes and the other has blue, brown eyes is one allele and blue eyes is one allele.

4. Alleles Every sex cell has one allele for each trait.
The study of how traits are inherited through the interactions of alleles is the science of genetics.

5. Mendel-Father of Genetics
Gregor Mendel began experimenting with garden peas in
Mendel was the first to trace one trait through several generations.
He was also the first to use the mathematics of probability to explain heredity.

6. Purebred
An organism that always produces the same traits generation after generation is called a purebred.

7. Hybrids
Hybrids—an offspring that has been given different characteristics from each parent.
For example if your mother gave you the allele for blue eyes and your father gave you the allele for brown eyes, that is a hybrid.

8. Hybrids If you combine two purebred organisms, you would get a hybrid.
For example if a purebred lab is bred with a purebred poodle, you would get a hybrid called a labradoodle.
This is called
cross-pollination

9. Dominant and Recessive Genes
The dominant factor is the one that “dominates” or covers up the other factor.
The recessive gene is the one that seems to disappear.

11. Probability
We can use probability to determine the odds of an offspring having a characteristic.

12. Punnett Squares
In a Punnett square, letters represent dominant and recessive alleles.

13. Punnett Squares An uppercase letter stands for a dominant allele.
A lowercase letter stands for a recessive allele.

14. Harry Potter and the Recessive Allele
How Are Wizards Made?

15. 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

16. How Are Wizards Made? The allele for wizarding ability is m
Wizards have the alleles mm

17. 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

18. The Malfoys Narcissa Malfoy (mm) Lucius Malfoy (mm) Draco Malfoy (mm)
The Malfoys are a ‘pure blood’ family
All their ancestors are wizards so they must have the alleles mm

19. The Potters James Potter (mm) Lily Potter (mm) Harry Potter (mm)
Both Harry’s parents had magical ability so they must both have been mm
They passed these alleles on to Harry

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

21. Mm Mm mm Hermione is a powerful witch so she must be mm
Both her parents are muggles so they must be Mm so they can give her a m allele each Mm Mm mm

22. Mm mm mm Tom Riddle is a ‘half blood’.
His mother was a witch (mm) and his father was a muggle
His father must have had the alleles Mm so he could give him the other m allele Mm mm mm

23. What wizarding alleles would Ron and Hermione’s children have?
Ron (mm)
Hermione (mm)
Children
(mm)

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

25. What wizarding alleles would Ginny and Dudley’s children have?
If Dudley is Mm
Dudley Mm
Ginny mm
Children m M m m

26. 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
Dudley m M
Ginny m m m M m m m M

27. What wizarding alleles would Ginny and Dudley’s children have?
If Dudley is MM
Dudley MM
Ginny mm
Children m M

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

29. What wizarding alleles would you expect Hermione’s
brothers and sisters to have?

30. Mr Granger m M Mrs Granger WW WM m m m M m M M M
The Granger’s children have a one in four chance of getting m alleles from both parents and having magical ability
They also have a one in four chance of getting M alleles from both parents and being a muggle
They could also
get only one
m from their
mother or father
and still be a
muggle
Mr Granger m M
Mrs Granger WW WM m m m M m M M M

31. Genotype and Phenotype
Genotype is the genetic makeup of an organism.
The way an organism looks and behaves as a result of its genotype is its phenotype

33. Homozygous
An organism with two alleles that are the same is called Homozygous.

34. Heterozygous
An organism that has two different alleles for a trait is called heterozygous.

35. Making a Punnett Square

36. Incomplete Dominance
When the offspring of two homozygous parents show an intermediate phenotype, this inheritance is called incomplete dominance.
See picture of horses on pgs

37. Sex Determination
When a sperm with an X chromosome fertilizes an egg, the offspring is a female, XX.
A male offspring, XY is the result of a Y-containing sperm fertilizing an egg.

38. Sex-Linked Disorders
An allele inherited on a sex chromosome is called a sex-linked gene
Color blindness is a sex-linked disorder in which people cannot distinguish between certain colors, particularly red and green.