Mendelelian Genetics Flashcards
Responsible
for the Laws
governing
Inheritance of
Traits
Gregor Mendel
Year of Gregor Mendel
1882-1884
Gregor Mendel made the law that governing what
Inheritance of traits
What are the 3 laws of inheritance?
- Law of Dominance
- Law of Segregation
- Law of Independent
Assortment
Mendel stated that
physical traits are
inherited as
particles
Mendel did not know
that the “particles”
were actually
chromosomes and dna
Between , Mendel
cultivated and
tested some 28,000
pea plants
1856 and
1863
Mendel
cultivated and
tested some
28,000
pea plants
He found that the
plants’ offspring
retained
traits of
the parents
Gregor Mendel is called as the father of ?
Genetics
Site of Gregor
Mendel’s
experimental
garden in the
Czech Republic
State why Gregor Mendel chose the garden peas
- Can be grown in a small area
- Plants Reproduce at a fast rate
- Thus, a number of generations can be produced within a short time
- They are hardy plants which do not need much caring and cultivating
- Plants produce lots of offspring
- Produce pure plants when allowed to self-pollinate several generations
- Can be artificially cross-pollinated
- Garden pea has several contrasting characters
Pollen contains sperm
Produced by the
stamen
Ovary contains eggs
Found inside the
flower
Pollen carries sperm to the
eggs for
fertilization
can
occur in the same flower
Self-fertilization
can
occur between flowers
Cross-fertilization
How Mendel Began his expt.
Mendel produced pure strains by allowing the
plants to self-pollinate for several
generations
why did Mendel produced pure strains by allowing the
plants to self-pollinate for several
generations
This way he was sure that the character (ex. round seeds) was “pure breed”. All the pea plants which he cultivated for this purpose produced only “round seeds”
He describe such plants
which produce the same
character from generation
to generation as
pure-breeding or “breed
true”.
SECOND step of the experiment:
he cross pollinate the pure breed of round
seeded plants with the wrinkled seeded
plants
Mendel hand-pollinated
flowers using a
paintbrush
He could snip _____ to prevent
self-pollination
Covered each flower
with a cloth bag
the
stamens
any characteristic that
can be passed from parent to
offspring
trait
passing of traits
from parent to offspring
Heredity
study of heredity
Genetics
cross
involving a single trait
e.g. flower color
Monohybrid cross
cross involving
two traits
e.g. flower color & plant height
Dihybrid cross
Organisms with two sets of chromosomes are
called
diploid organism
These chromosomes contain the genes that code
for the same traits
diploid organism
The trait that is observed in the
offspring is the
dominant trait
Genes that code for alternate expressions
(alleles)
The trait that disappears in the
offspring is the
recessive trait
A_______s a piece of DNA that directs a cell
to make a certain protein.
gene
Each gene has a____________, a specific position on
a pair of homologous chromosomes.
locus,
An_________ is any alternative form of a
gene occurring at a specific locus on a
chromosome.
Each parent donates one
allele for every gene.
allele
describes two
alleles that are the same at
a specific locus.
Homozygous
describes two
alleles that are different at
a specific locus.
Heterozygous
gene combination
for a trait
genotype
the parental
generation in a breeding experiment.
Parental P1 Generation
the first-generation
offspring in a breeding experiment. (1st
filial generation)
Parental P1 Generation
the second-generation
offspring in a breeding experiment.
F2 generation
THIRD step of the
experiment:
he cross plants from the breeding
individuals of the F1 generation
It results to F2 generation = the
second-generation offspring in a
breeding experiment.
explained the heredity of
the offspring of the f1 generation
law of dominance
explained the heredity of
the f2 generation
law of segregation
In a cross of parents that are
pure for contrasting traits, only
one form of the trait will appear in
the next generation.
Law of Dominance
-During the formation of gametes (eggs or
sperm), members of the pair/two alleles
responsible for a trait separate from each
other so that only one member is included in
each gamete.
Law of Segregation
Refer to hereditary patterns
that are not in accordance with
Mendel’s principles or those
that are not attributed to
single autosomal genes.
Refer to hereditary patterns
that are not in accordance with
Mendel’s principles or those
that are not attributed to
single autosomal genes.
F1 hybrids have an appearance somewhat
in between the phenotypes of the two
parental varieties.
Incomplete Dominance
produces the
F1 generation
Incomplete Dominance
-When one allele is not completely dominant
to another allele
- With incomplete dominance the
heterozygote’s phenotype is between that of
individuals homozygous for either individual
allele involved.
INCOMPLETE DOMINANCE
(Partial dominance)
Is a modification of a dominance
relationship that is related to
incomplete dominance
Codominance
