Transcript Genetics
Genetics
Genetics and Mendel!
Mendel (b. 1822) in Czech Republic,
moved to Vienna, Austria
Worked as a monk and a HS teacher,
gardened in spare time….
Little did he know his work would be
the foundation of modern genetics
Genetics: the scientific study of
heredity—the core of biology!
Vocabulary
Fertilization: The process were male
and female GAMETES unite.
True breeding: Self-fertilization, it
occurs when male gamete within a
flower combines with a female gamete
in the same flower.
Cross pollination: Pollen from one
flower fertilizes a second different
flower.
Trait: A specific CHARACTERISTIC
that varies for one INDIVIDUAL to
another.
Generations
F1= First Filial (offspring), F2= Second Filial
Vocabulary
Hybrid: The offspring of crosses
between parents with different TRAITS.
Genes: A sequence of DNA that codes
for a protein and thus determines a
trait.
Alleles: Different forms of a TRAIT.
Mendel’s Conclusions
Biological inheritance is determined by
TRAITS that are passed from one generation
to the next.
Today we call Mendel’s factors:
Traits=Genes, Form= Allele
Every trait is controlled by one GENE that
occurs in 2 contrasting forms called ALLELES.
Principle of Dominance
Some alleles are DOMINANT and some
are RECESSIVE
An organism with a dominant allele for
a trait will ALWAYS exhibit that form of
the trait.
An organism with a recessive allele for
a trait will exhibit that form only if the
dominant allele is NOT present.
Segregation
Medel’s question, “Did the recessive
alleles disappear?”
Principle of Segregation
Segregation
= Separation
The separation of alleles occurs
during the process of MEIOSIS
when gametes are formed. Each
gamete carries a single copy of
each gene.
Vocabulary
Homozygous: two identical alleles (TT) or
(tt)
Heterozygous: two different alleles (Tt)
Phenotype: physical or outward
appearance (ex: tall, short, yellow, green)
Genotype: genetic makeup (TT, Tt, Gg,
gg)
In Short…
Capital Letters (T) = Dominant Trait
Lowercase Letters (t) = Recessive Trait
T= Tall and t= short
Homozygous: Having 2 IDENTICAL
alleles for a trait. (TT) or (tt)
Heterozygous: Having 2
DIFFERENT alleles for a trait. (Tt)
Prediction Uses Probability,
not magic!
Probability- likelihood a particular
event will occur
We can study Mendel’s crosses with
Punnett Squares (diagram that shows
gene combinations from a genetic
cross)
Used to predict and compare the
genetic variations that can occur
How Punnett Squares Work