Mendelian Genetics. Study of heredity developed by Gregor Mendel. Mendel’s Three Laws. Law of Dominance Law of Independent Assortment Law of Segregation. Genetics- study of heredity Trait- a characteristic that can be passed from parent to offspring.
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Study of heredity developed by Gregor Mendel
Law of Dominance
Law of Independent Assortment
Law of Segregation
Trait- a characteristic that can be passed from parent to offspring.
Gregor Mendel – “the father of modern genetics” used pea plants to study how traits were passed on among generations.
Applied mathematics to make statistics on how traits are passed along.
He was able to isolate and control variable.
- Cut anthers and only pollinated with desired pollen
Purebred- an organism that possesses identical alleles for a particular trait.
-homozygous (same alleles)
- receives the same genetic traits from both parents
Hybrid- an organism that possesses different alleles for a particular trait.
-heterozygous (different alleles)
P = parental
F1 = filial (offspring) first generation
F2 = second generation
Which trait is dominant?
Chartreuse is dominant.
Predicting the likelihood of an event or outcome.
Using fractions, percentages, or ratios.
1/2 50% 1:1
Used to predict the phenotypes and genotypes of offspring in breeding experiments.
Can even predict the numbers of kinds offspring before fertilization takes place.
Scientists use a tool to make these predictions.
YY x yy
Cross a heterozygous yellow pea plant with a heterozygous yellow pea plant.
F1 Yellow vs F1 Yellow
Apply the same rules of probability.
The inheritance of two traits at the same time - dihybrid cross
Cross two heterozygous round, heterozygous yellow pea plants.
Punnett square 4 x 4.
Use a Punnett square, show genotypic ratios and phenotypic ratios.
RrYy x RrYy
If dominant, how do you know whether it is homozygous or heterozygous?
By doing a test cross.
Test cross- crossing the organism with an unknown genotype with a homozygous recessive organism.
If the unknown genotype is heterozygous, Yy, about 50%the offspring should show the recessive phenotype.
If the unknown genotype is homozygous, YY, 100% the offspring will show the dominant phenotype.
Figure 6.10 shows this.
How do you know if the plant is a heterozygous or homozygous tall wheat plant?
Tall wheat plant x short wheat plant
Ability to roll tongue x inability to roll tongue
What is the genotype of the parent with the ability to roll their tongue, if they have 2 children that can roll their tongue and 2 children that cannot?