Introduction to Genetics

1. Chapter 2
Getting into the Genes

2. Learning Intensions
• You will describe DNA and its role as the
blueprint for controlling the characteristics of
organisms
• You will iIdentify the different types of
Chromosomes and understand their role in
genetics
• You will use inquiry skills to perform an
experiments on working with DNA

3. 2.1 Patterns,
order and organisation:
nuclear matters
pg. 50

4. Class Discussion and Title Page

5. Your Group Quest
Complete Think, Share and Discuss
pg. 49
Q 1 to 4 and 5

6. How can this be?

7. Black and white twins again.
Saturday, January 24th, 2009.
The two-tone miracle repeated
after 7 years for the mixed-race
couple Dean Durrant and Alison.
When the first set of twins arrived
in 2001, the couple were
astonished to see that Lauren
took after her white mum, with
blue eyes and red hair, while
Hayleigh had black skin and hair
like dad Dean.
Then this year Alison, 27, found she
was expecting again — and
lightning struck twice.
She had twin girls again. And little
Miya was born with dark skin like
her dad and Leah is white like
former recruitment consultant
Alison.

8. Nigerian Family Gave Birth To White
Girl With Blue Eyes
Monday, July 26, 2010, 10:28
British black family gave birth to a baby
girl with white skin, blue eyes and fair
hair. Doctors say that the newly born
is not an albino. The family had three
children who, like their parents, have
black skin.
Gene experts can’t explain how Nigerian
couple could give birth to a European
looking child.
Brain Sacks from the Oxford University
says that the birth is extraordinary.
Giving birth to such child should mean
any white ancestors of the parents.
But Ben and Angela Ihegboro claim
they don’t remember any relatives
who even remotely looked like
whites.

9. Think, Share and Discuss
1. Record any patterns.
2. If second generation had
another child, suggest what eye
colour they may be and give a
reason.
3.Suggest a reason why second
generation had brown and blue
eyed children.
4. Suggest a reasons why Third
generation had only blue eyed
children.
5. if the female in Fourth
generation married a man also
with blue eyes, what colour eyes
could their children have?

10. Genes are located in all our
cells. How complex are our cells?
Have you ever wondered what we are all made of?

11. Game – DNA Challenge
Use Worksheet to complete A to Z.
Deoxyribonucleic acid
• How many words can you make out of this word.
• 4 mins INDIVIUALLY
GO..................
• Prize for top 3 students with most words – Lollies

12. Cell Nucleus Chromosome Gene DNA
DNA –
deoxyribonucleic
acid
 Molecule
Found in nucleus
Genetic code
passed on through
generations
Makes your
features / traits eg.
Ear lobes / widows
peak
DNA

13. Genes
Each set (group of DNA) that
code for a trait / feature
eg. Eye colour, longer
second toe = GENE
Many genes make a larger
structure ………

14. …..the chromosome
Chromosomes are a long, continuous
pieces of DNA (groups of genes),
found in the nucleus of our cells.
Chromatid is one of the two identical
parts of the chromosome.
Centromere is the point where the two
chromatids touch
Short arm and the long arm

15. Pairs - Copy the following diagram and
label
• Each pair of
chromosomes contain
one chromosome from
your father and one
from your mother.
• This is how you get a
mixture of genes,
therefore
characteristics from
both parents.
Chromosome pair number
1
Chromosome
Chromatid Chromatid
A pair
Gene Gene

16. Read only - Your eyes are
green
But his are grey and mine
are brown.
This is all caused by how
the DNA is structured to
make the gene.
Green eyes??? Hazel eyes???
The eye color is given by the amount of
melanin (same pigment as for hair and
skin). The higher the melanin, the darker
the eye color, and vice-versa. Green and
Hazel linked with Brown eyes – Brown
eyes can have many shades of colour.
Blue eyes only have blue.

17. Video

19. Write these questions leaving a couple of lines and
answer them using the following slides
• 1.How many chromosomes do humans contain?
• 2.How many pairs do we contain?
• 3.What is pair number 23 called? Why?
• 4. What do we call all the other normal chromosomes pair no. 1 to 22?
• 5. What sex chromosomes would
i) male
ii) Females have?
• 6. Define Karyotype
• 7. Define Homologous chromosome
• 8. Define Non-homologous chromosome
• 9. Define mitosis?
• 10. Define gamete cells?
• 11. Define somatic cells?
• 12. How many chromosomes are in an egg?
• 13. How many chromosomes are in the sperm?
• 14. Why do gametes or sex cells (egg an sperm) only contain 23 single
chromosomes not 46 like all the other normal cells in the body?

20. Chromosome Number
Humans have 23 pairs
of chromosomes or 46
individual
chromosomes in every
normal cell.
Chromosomes can be
placed in pairs from
largest to smallest.
Autosomes – all the
normal chromosomes
pair no. 1 to 22.
Sex Chromosomes –
pair no. 23 – determines
your gender
Female = XX
Male = XY
Karyotype -the
no. and
appearance of
chromosomes in
the cells
nucleus.

21. Autosomes
• Homologous = matching /
same pairs of
chromosomes
• eg. chromosome 1 and 1
• Each pair same size, same
banding pattern and contain same
genes for traits, 1 from mum and
1 from dad
• Non-homologous = non
matching chromosomes
eg.chromosome 21 and
3
Mum Dad

22. Table 1: Examples of chromosome
numbers (diploid).
•Species
# of
chromosomes
Species
# of
chromosomes
Fruit fly 8 Human 46
Rye 14 Ape 48
Guinea Pig 16 Sheep 54
Dove 16 Horse 66
edible snail 24 Chicken 78
Earthworm 32 Carp 104
Pig 40 Butterflies ~380
Wheat 42 Fern ~1200

23. STOP • Circle each chromosome
pair (its matching
chromosome with the
same size and pattern),
number each biggest
being number 1,down to
smallest being number 22
and with sex
chromosomes at the end
being number 23. If time
you could cut and paste in
order as shown. See
picture here for example.
• Determine the gender.
Activity –
See Karyotype
Normal worksheet.

24. Investigation
2.1
• Alternative
Practical to pg. 53
• Extracting DNA
from Strawberries.
• Refer instructions
sheet.
Working
with DNA

25. Textbook Exercises pg. 54
Remember questions:
1.(a to k), 2, 3, 4, 5 (a, b, c, d, g)
* 6 all