- Gregor Mendel is known as the "Father of Genetics"
- Crossbred pea plants in the monastery garden.
- Was a mathematician and botanist.
- Did experiments that provided scientists with an understanding of how traits are inherited between generations
- in mendel's time traits of the parents were thought to mix or blend together in order to form the offspring.
- they did not understand how traits could be expressed without being diluted
- he selected seven traits to study: seed shape, seed color, pod shape, pod color, plant height, flower color,and flower position.
- he used pea plants because they are pure breeding; this means that they produce offspring that are identical to themselves because they self pollinate.
- pea plants grow fast and have traits that appear in only two forms.
- Monohybrid cross
- Law of Segregation- organisms donate a single unit of inheritance in their gametes (sex cells), and the two copies separate or segregate during gamete formation.
- Another unit that emerged from his data is that some units are dominant over other units.
- Int the cross between the tall and short plant, the unit for tallness was dominant over the unit for shortness. When the unit for tall plants is combined with the unit for short plants, tall plants are always produced. The unit that seems to disappear is called recessive.
- Recessive traits can only be expressed when there are two units combined together for that trait.
- the distinct hereditary units are called genes
- genes are located on chromosomes
- Humans have 46 chromosomes, they receive 23 from their mom and 23 from their dad
- the location of a gene on a chromosome is called a locus
- Each form of a gene is called an allele.
- Homozygous means the alleles are identical
- Heterozygous means the alleles are different
- Phenotype is the physical appearance
- Genotype is the code for the specific gene
- Punnett squares show probability in genetic crosses.
Discussion Questions
- Mendel was able to control the experiments by cutting off the male sex part and pollinating the female.
- Mendel got a 3:1 ratio on the Punnett square which led to the law of segregation.
- The Punnett square helped Mendel predict how the offspring would look and what genotypes they would have.
- The terms genes, homologous chromosomes, alleles, locus, dominant, and recessive are related because