Feeling Lost??
Why Do They Matter?
They occur during the second part of Meiosis
a. Produces eggs and sperm cells.
2. Because of the law of segregation, it ensures that each egg
or sperm receives one copy of each chromosome.
Why does that matter? This reduction division keeps the
chromosome number consistent between the generations
of parents & offspring.
1.
23
23
46
Why Do They Matter?
3. Because of the law of independent assortment, it
provides variation in the offspring so that they all do
not look the same and have the same characteristics.
4. Statistically, it is POSSIBLE for all offspring to
resemble each other, but it is IMPROBABLE that
they will
It’s the equivalent of the genetic lottery!
Understanding the Law of Segregation
Segregation: The act or process of separating or setting
apart.
As the name of this implies, segregation means that certain
things are being separated from each other.
So, what is being separated?
The homologous pairs of chromosomes.
#3
#2
#4
#1
Homologous Pairs
Before Segregation
Pink: the one received
from “mom”
Blue: the one received
from “dad”.
Homologous Pairs
After Segregation
Note That I changed the
color to black for all 4
pairs. What we need to
understand is that the
pairs separate from their
“match” and move to
the opposite side of the
cell before it divides.
Law of Independent Assortment
1. When the
homologous pairs
separate, there is no
way to predict which
resulting egg or
sperm they will end
up in.
2. This really comes
down to chance,
probability and the
“luck of the draw”.
What Does Independent
Assortment Look Like?
Here is one example of
how it might look.
We will use numbers
to represent the
chromosome pairs.
Pink are from mom,
blue were inherited
from dad.
11223344
5566778
8 9 9 10 10
11 11 12 12
1 2 3 4
5 6 7 8
9 10 11
12
1 2 3 4
5 6 7 8
9 10 11
12
 Or it could look
like this:
11223344
5566778
8 9 9 10 10
11 11 12 12
1 2 3 4
5 6 7 8
9 10 11
12
1 2 3 4
5 6 7 8
9 10 11
12
11223344
5566778
8 9 9 10 10
11 11 12 12
1 2 3 4
5 6 7 8
9 10 11
12
1 2 3 4
5 6 7 8
9 10 11
12
 It’s all based on CHANCE!
 You are the result of a winning combination!