mendel and meiosis gregor mendel an austrian monk from the mid- nineteenth century, carried out...

Mendel and meiosis • Gregor Mendel an Austrian monk from the mid-nineteenth 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.

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Mendel and meiosis • Gregor Mendel an Austrian monk from

the mid-nineteenth 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.

Page 2: Mendel and meiosis Gregor Mendel an Austrian monk from the mid- nineteenth century, carried out studies of heredity,--the passing on characteristic from

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.

Page 3: Mendel and meiosis Gregor Mendel an Austrian monk from the mid- nineteenth century, carried out studies of heredity,--the passing on characteristic from

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.

Page 4: Mendel and meiosis Gregor Mendel an Austrian monk from the mid- nineteenth century, carried out studies of heredity,--the passing on characteristic from

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.

Page 5: Mendel and meiosis Gregor Mendel an Austrian monk from the mid- nineteenth century, carried out studies of heredity,--the passing on characteristic from

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.

Page 6: Mendel and meiosis Gregor Mendel an Austrian monk from the mid- nineteenth century, carried out studies of heredity,--the passing on characteristic from

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.

Page 7: Mendel and meiosis Gregor Mendel an Austrian monk from the mid- nineteenth century, carried out studies of heredity,--the passing on characteristic from

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.

Page 8: Mendel and meiosis Gregor Mendel an Austrian monk from the mid- nineteenth century, carried out studies of heredity,--the passing on characteristic from

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.

Page 9: Mendel and meiosis Gregor Mendel an Austrian monk from the mid- nineteenth century, carried out studies of heredity,--the passing on characteristic from

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.