Transcript Mendel and meiosis

Mendel and meiosis
• Gregor Mendel an Austrian monk from the midnineteenth century, carried out studies of
heredity,--the passing on characteristic from
parents to the offspring.
• Traits,--are the characteristic that are inherited.
• Mendel was the first person to succeed in
predicting how traits are passed from one
generation to the next.
Genetics and stuff
• Genetics,--the branch of biology that studies
heredity.
• Gametes,--are the male and female sex cells
• The male gamete forms in the pollen grain,
which is produced the male sex organ. The
female gamete forms into a female sex organ.
• Fertilization, when a male gamete unites
with a female gamete
• Zygote,-- is a fertilized cell.
Pollination
• Pollination,--The transfer of pollen
grains from a male reproductive organ
to a female reproductive organ
• In peas both organs are located in the
flower.
Mendel's Monohybrid crosses
• Mendel crossed bred plants with other
plant and he called the cross breeds
Hybrids,--is an offspring of parents
that have different forms.
• Mendel’s first experiments are called
monohybrids, mono means “one” and
the two parent plants differed from
each other by a single trait—height.
The rule of unit factors
• Genes exist in alternative forms. We call
these different gene forms Alleles.
• For example each of Mendel's pea plants had
two alleles of the gene that determined its
height.
• An organism’s two alleles are located on
different copies of a chromosome—one
inherited from the female parent and one
from the male parent.
Dominance and Recessive
• Dominance,--observed trait of an
organism.
• Recessive, trait of an organism that
can be masked by the dominate form of
a trait.
Segregation
• Law of segregation,--Mendelian
principal explaining that because each
plant has two different alleles, it can
produce two different types of gametes.
• During fertilization, male and female
gametes randomly pair to produce four
combinations of alleles.
Genotype and phenotype and
homozygous
• Genotype,--is the combination of
genes in an organism.
• Phenotype,--is the outward
appearance of an organism regardless
of its genes.
• an organism is Homozygous,-- for a
trait if its two alleles are the same.
Punnett squares
• In 1905, Reginald Punnett, an English
biologist, devised a shorthand way of
finding the expected proportions of
possible genotypes and offspring of a
cross. This method is called a Punnett
Square.
Law of independent assortment
• Law of independent assortment,-Mendelian principle stating that genes
for different traits are inherited
independently of each other.
Probability
• Punnett squares are good for showing
all the possible combinations of
gametes and the likelihood that each
will occur.