Transcript day 1- mendels work

Objective: To understand how
Mendel used math to predict
offspring traits
• Bellwork question: what is the difference
between probability and reality?
Today’s agenda:
1. Discuss mendel’s work
2. Use probability to create a baby
Do you look exactly like 50% of
your mother and 50% of your
father?
Day 1: KEY CONCEPT
Mendel’s research showed that
traits are inherited as discrete
units.
Genetics
• Our focus in this unit is genetics -- the
study of how characteristics are
inherited.
• Keep in mind that the environment plays
a role. That is why outcomes don't
always match our expectations.
Terms to understand about
Genetics
• Heredity- the passing on of traits to
offspring
• Genetics- the study of heredity. How
exactly those traits gets passed on. Why
is it that you don’t always get what you
expect?
Alleles
• Different version of the same gene.
• Same loci- Always on the same place on
the same chromosome.
• Will result in a trait. In most cases, a gene
is either dominant or recessive
• Symbols for alleles will always be a single
letter
When you have 2 copies of each
gene, which shows through?
• Dominant- the gene which is expressed no
matter what the other allele is. Represented by
upper case symbol
• Recessive- will be overshadowed in the
presence of a dominant gene. 2 copies of a
recessive allele must be present for the trait to
show up. Represented by lower case symbol
• There are some cases where genes follow more
complicated rules. More on that next week
More terms…
• Homozygous- literally
“same seed”. Both
alleles are the same
either both are dominant
or both are recessive
• Heterozygous- literally
“different seed”. Alleles
are different, one
dominant and one
recessive.
More terms…
• Genotype- your genetic
make-up
• Phenotype- your physical
characteristics. The
expression of the genes.
• Genome- a collection of
all your genes. The
complete recipe to make
you be you.
Mendel
• Was a monk and a
mathematician
• Studied ratios and probability
as he grew crops
• Discovered the laws of
inheritance
• https://www.youtube.com/wat
ch?v=0vAAf4g5iF8
Mendel laid the groundwork for
genetics.
• Traits are distinguishing characteristics that are
inherited.
• Genetics is the study of biological inheritance patterns
and variation.
• Gregor Mendel showed that traits are inherited as
discrete units.
• Many in Mendel’s day thought traits were blended
(equal combination of mother and father)
• Mendel used pollen to fertilize selected pea
plants.
– P generation (parental) crossed to produce F1
generation (family 1)
– interrupted the self-pollination process by
removing male flower parts
Mendel controlled the
fertilization of his pea plants
by removing the male parts,
or stamens.
He then fertilized the female
part, or pistil, with pollen from
a different pea plant.
• Mendel allowed the resulting plants to selfpollinate.
– Among the F1 generation, all plants had purple
flowers
– F1 plants are all heterozygous
– Among the F2 generation, some plants had
purple flowers and some had white
Mendel observed patterns in the first and
second generations of his crosses.
What is this ratio ____:_____?
• Mendel drew three important conclusions.
– Traits are inherited as discrete units.
– Organisms inherit two copies of each gene, one
from each parent.
– The two copies segregate
during gamete formation.
– The last two conclusions are
called the law of segregation.
purple
white
Mendel- finally putting it all
together
• 1865 Gregor Johann Mendel presents his
principals of heredity [particulate
inheritance] to the Brunn Society for
Natural History and publishes in the
Proceedings of the Brunn Society for
Natural History in the following year
Mendel's work showed that:
1. Law of Dominance
2. Law of Segregation
3. Law of Independent Assortment
Law of DominanceEach parent contributes one factor (gene) of
each trait shown in offspring.
One gene will be dominant over the other.
Law of SegregationThe two members of each pair of factors
segregate from each other during gamete
formation
This describes the process of meiosis I
Law of Independent
AssortmentThe alleles for different genes go into
different gametes
Why you are not an
even ¼ of each
grandparent
Kahoot
• https://create.kahoot.it/#quiz/004d774226ec-4c36-a399-f000c15b5c7d
Make a baby lab
• You can move for this.
• You will need
– A partner (groups of 2 for baby making)
– A coin to flip
• Heads= dominant
• Tails= recessive
– A piece of paper
– instructions for the group of 2 to share
– List traits and draw baby on the back of
lecture notes
Fashion photographer
• http://photoblog.nbcnews.com/_news/2013
/06/07/18831654-fashion-photographerfocuses-on-those-with-genetic-conditionsto-reframe-beauty