Download Using Meiosis to make a Mini-Manc

Using Meiosis to make a Mini-Manc
INTRODUCTION
This activity demonstrates the principles of Independent assortment of chromosomes
and shows how meiosis leads to tremendous genetic variation.
Mini-Manc’s are creatures that live in the YOUR SCHOOL AREA, feeding on the
dead skin of students. They are shy creatures, – they only come out at night – so
you’re very lucky to see one. But most importantly, Mini-Manc’s are excellent
subjects for genetic study, because they have some very distinctive features.
IMPORTANT INFORMATION!
•
Mini-Manc’s have 7 pairs of homologous chromosomes – these are
represented by 7 pairs of different coloured card.
•
The sex chromosomes X and Y are represented by white card.
•
We are going to follow the inheritance of 7 different features (phenotypes),
carried on 7 different pairs of chromosomes.
•
Mini-Manc’s have 2 copies (alleles) of each gene, carried on different pairs of
chromosomes.
E.G. A Mini-Manc of genotype Aa carries allele A on one (orange)
chromosome and allele a on its homologous chromosome (orange)
See Table 2 for possible phenotypes & genotypes of a Mini-Manc. To check you
understand this table, fill in the phenotypes of the parent Mini-Manc in Table 1.
Table 1
Mini-Manc’s Parents
Aa
Bb
Dd
Gg
Hh
Qq
Chromosome
Colour
Orange
Blue
Pink
Green
Yellow
Purple
XY
XX
White
White
Genotype
Table 2
Phenotype
NOTE!
EVERYONE WILL BE
STARTING WITH
PARENTS OF EXACTLY
THE SAME GENOTYPE
– THE ONLY
DIFFERENCE BEING
THAT SOME OF YOU
WILL HAVE MALE MINI
MANC’S AND SOME
WILL HAVE FEMALES
Your Baby Mini Manc
YOUR MINI MANC
Feature
Phenotype
(Appearance)
Antennae
Orange
Antennae
Blue Antennae
Number of
Three Eyes
Eyes
Two Eyes
One Eye
Colour of Legs
Pink legs
Purple legs
Colour of Body Green body
Yellow body
Colour of Tail
Golden Tail
Red Tail
Shape of Tail
Curly Tail
Straight Tail
Sex
Male
(White Nose)
Female
(Pink Nose)
Genotype
(Genetic
makeup)
AA or Aa
aa
BB
Bb
bb
DD or Dd
dd
GG or Gg
gg
HH or Hh
hh
QQ or Qq
qq
Chromosome
Colour
Genotype
Orange
Blue
Pink
Green
Yellow
Purple
XY
White
XX
White
Phenotype
Figure 1 Creating your Mini Manc
Antenna
(small bent pipe cleaner: orange or blue)
Eyes
(drawing pins: 1,2 or 3)
Tail
large pipe cleaner: gold or
red; straight or curly)
Nose
(marsh mallow on
cocktail stick:
pink or white)
Legs
(cotton buds: pink or purple)
Body
(pan scourer: yellow or green)
MIXED UP MEIOSIS
1. On your own, place your cards face down and shuffle them about.
These cards represent your parent Mini Manc’s chromosomes (diploid number).
2. Leave the cards face down and put them into homologous (coloured) pairs.
Chromosomes actually do pair up like this during Prophase I of meiosis.
3.
Pick one card –any card- from each pair
This simulates independent assortment of the chromosomes during Metaphase
II, where the arrangement of the chromosomes above and below the spindle
fibre equator occurs at random.
4. You should now have 7 cards, one of each colour.
This set of cards represents your gamete (egg or sperm), which has half the
number of chromosomes of your parent Mini Manc (haploid number).
5. Now mate with your partner! Combine your 7 cards with your partner’s.
This simulates random fertilisation. Remember you could have mated with any
other Mini Manc in the class!
6. Congratulations! You are pregnant! Bet you can’t wait to see what your
baby is going to look like! It’s time to record your Baby Mini Manc’s
genotype (genetic makeup) in Table 2 and work out its phenotype
(appearance).
7. TIME TO GIVE BIRTH! Use your data in Table 2 to create your Baby Mini
Manc (use figure 1 to help you).
8. When you have finished, we will compare class results.
o Are any two Baby Mini Manc’s from our class the same?
o If not, why not?
o What other event during meiosis can create even more genetic
variation?
9.
If you have time, take the sets of cards (gametes) that you and your
partner did not use during fertilization. How would your Mini Manc’s
appearance have been different had you used these gametes instead of
the ones you chose first time round?
TEACHERS NOTES
Equipment Required (per pair of students)
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
3 drawing pins
2 small pipe cleaners (one orange one blue)
2 large pipe cleaners (one red one gold)
2 small marshmallows (one pink one white)
8 cotton buds (four pink four purple)
2 pan scourers (one green one yellow)
2 x Orange card with “A” printed on.
2 x Orange card with “a” printed on.
2 x Blue card with “B” printed on.
2 x Blue card with “b” printed on.
2 x Pink card with “D” printed on.
2 x Pink card with “d” printed on.
2 x Blue card with “B” printed on.
2 x Green card with “G” printed on.
2 x Green card with “g” printed on.
2 x Yellow card with “H” printed on.
2 x Yellow card with “h” printed on.
2 x Purple card with “Q” printed on.
2 x Purple card with “q” printed on.
1 x White card with “Y” printed on.
3 x White card with “X” printed on.
Relevance to GCSE syllabus
AQA:
B2.7.1 Cell division
Edexcel:
Unit B2: The components of life
Topic 1: The building blocks of cells