Transcript Mendel Discovers “Genes” 9-1

Genetics
Transmission of characteristics from
parents to offspring
_______________________is
called
___________________.
heredity
how those
science that studies _____
The _________
characteristics are _________
passed on from one
generation to the next is called
Genetics
_______________.
The _________________
Father of Genetics
is _________________.
Gregor Mendel
A monk, who studied
how to use
____________
mathematics to
explain natural
phenomena.
Mendel designed
experiments using
____________
pea plants in the
__________
monastery garden.
_______
MALE part of flower makes
Pollen
___________
(sperm)
FEMALE
__________ part of flower makes
egg cells
_______
In pea plants, the pollen normally joins
with an egg from the _______
same plant
(=_______________
Self pollinating ) so seeds have
“_______________”
ONE parent
MENDEL’S PEA EXPERIMENTS
Mendel started his experiments with
peas that were _________________
true breeding
= if allowed to
_________________
self pollinate
they would produce
____________________
offspring identical
to themselves.
MENDEL’S PEA EXPERIMENTS
removed pollen
Mendel ____________________
making parts and ____________
added pollen
from _______
another plant.
This allowed him to
_____________
cross-breed plants
with ______________
different
characteristics and
study the results
________
specific characteristic is called a
A___________________
______.
trait
Mendel ______________
studied 7 traits in peas.
MENDEL’S EXPERIMENTS
P1 generation
____
(_________)
parental
F1 generation
____
filial
(______=
offspring)
F2 generation
___
MENDEL’S EXPERIMENTS
1.) Produce a true
breeding P generation
Self-pollination
P
X
Cross-pollination
2.) Produce an F1
Generation
F1
Self-pollination
3.) Produce an F2
Generation
F2
crossed PURE PLANTS
When Mendel ______________
with 2 ______________
traits:
contrasting
(EX: Purple crossed with white)
He always found same pattern:
1. ONLY ______
ONE trait ____________
showed
F1
in the ____
generation BUT . . .
Missing trait ____________
returned in
2. ___________
F2 generation
the ____
in a _________
3:1 ratio
Mendel decided that there must
pair of FACTORS that
be a __________________
control
________each
trait and that
__________
one factor must be able to
_______
HIDE the other.
We now know
that Mendel’s
factors
are genes
______________
carried on the
pair of
___________
homologous
____________.
chromosomes
____________
________
Different versions of a
gene are called _____.
alleles
DOMINANT
__________________
= An allele
hides the presence of
that ________
another allele
__________________
= An allele
RECESSIVE
that _______________
is hidden by the
presence of another allele
Why did the recessive trait disappear
in the F1 generation and reappear in
the F2?
The pattern corresponds
movement of
to the ____________
chromosomes during
______________
MEIOSIS
____________________
WHAT DOES MEIOSIS HAVE
TO DO WITH IT?
REMEMBER…
________________
HOMOLOGOUS
chromosomes
________________
SEPARATE
during
ANAPHASE I
= _________________
SEGREGATION
____
F1 offspring __________
received an allele for
the color purple from their _______
purple
parent and an allele for the color white
white parent.
from their ______
The F1 plants ALL _____________
look PURPLE
carrying an
but are ___________
allele for ______.
white
EXPLAINING the F1 CROSS
LAW OF ___________________
SEGREGATION
alleles are separated
when the F1 plants
______________
made gametes
When these gametes recombined to make the
recessive
F2 generation, the _____________
trait
_______________
reappears in ¼ of the offspring
Remember Mendel studied 7 traits…
LAW OF _______________________
Independent Assortment
alleles of different genes separate
independently of one another during gamete
formation.
We now know this only applies to genes
located on different chromosomes or that are
far apart on the same chromosome.
Let’s come back to alleles…
DOMINANT
__________________
= An allele
hides the presence of
that ________
another allele
_________________
RECESSIVE = An allele
that _______________
is hidden by the
presence of another allele
Genotype = the set of
_____________
alleles an individual has for a
characteristic.
_____________
Phenotype = the physical
appearance of a character.
A genotype can either homozygous
or heterozygous.
_____________
Homozygous = if two alleles for a
particular trait are ___________.
the same
______________=
Heterozygous if two alleles for a
particular trait are __________.
different
For example:
A mother has attached earlobes
(recessive) and a father unattached
earlobes. All their children have
attached earlobes.
What are the genotypes and
phenotypes of the mother, father,
and children?