11-3- Exploring Mendelian Genetics
Mendel wondered if the gene that determines whether a seed is round or wrinkled in shape have anything to do with the gene for seed color? Must a round seed also be yellow or do the ______separate independently.
Mendel’s next experiment is known as a ______-______cross (or dihybrid cross).
He followed ______different ______as they passed from one generation to the next.
The true breeding plants were :
Phenotypes: ______peas Genotype:______
Phenotypes: ______peas Genotype: ______
All offspring from this cross were (the F1generation):
Phenotype: ______Genotype:______
How did Mendel produce the F2 offspring? ______
What did Mendel observe in the F2 offspring that showed him that the alleles for seed shape segregate independently of those for seed color?______
What were the phenotypes of the F2 generation? ______
What was the ratio of Mendel’s F2 generation for a dihybrid or 2-factor cross?______
11-3 continued
Mendel’s principles:
1. The inheritance of biological characteristics is determined by individual units known as ______. In organisms that reproduce sexually, genes are passed from parents to their ______.
2. In cases in which 2 or more forms (or ______) of the gene for a single ______exist, some forms of the gene may be dominant and others ______.
3. In most sexually reproducing organisms, each adult has ______copies of each gene, one from each ______. These genes are usually segregated from each other when ______are formed.
4. The alleles for different genes usually segregate ______of one another. This is the Law of ______.
Beyond Dominant and Recessive
Cases in which one allele is not completely dominant over another are called ______. In incomplete dominance the ______phenotype is somewhere in between the 2 ______Phenotypes. In 4 O’Clock flowers the heterozygous phenotype is pink, the homozygous dominant is red, the homozygous recessive is white.
Cross a pure red with a pure white 4 O’Clock flower below:
Codominance is when both alleles contribute to the phenotype, so they don’t blend in the heterozygous phenotype, but both show up. An example is in chickens with a mix of black and white feathers. Both colors show up.
Multiple Alleles:
Sometimes more than ______possible ______exist in a population, but an individual can only possess 2 of them.. Examples are blood types in humans: there is A, B, or O alleles available and humans can only have 2 of the 3 available: AA, AO, BB, BO, OO, or AB. A and B are both dominant alleles, O is a recessive allele, so A and B together are considered codominant, because both show up.
Polygenic traits:
Many traits are controlled by two or more genes, and the interaction of these genes. Examples are eye color, skin color, and many more ______.
Polygenic traits often show a ______of phenotypes.
11-4 Meiosis
______are chromosomes that each have a corresponding chromosome from the opposite-sex parent.
______, (2N) which means “Two sets” is used to describe both sets of homologous chromosomes.
When there is only a single set of chromosomes, they are called:______. (N).
The process of reduction division in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell is called ______.
Meiosis has two stages called ______and ______.
During prophase in meiosis 1, each chromosome pairs with its corresponding homologous chromosome to form a structure called a ______.
Homologous chromosomes can also exchange parts of their chromatids in a process called ______.
Meiosis I results in two ______daughter cells, each with ______the number of chromosomes as the original cell.
Meiosis II results in ______(N) daughter cells.
MEIOSIS CREATES GAMETES (SEX CELLS) WITH HALF THE NUMBER OF BODY CELLS!!!!
11-5: Linkage and Gene Maps
Why is Thomas Hunt Morgan important in genetic studies?
What is gene linkage?
How does gene linkage affect the usual ratios found when working Punnett Squares?
What is a gene map?
How are the locations of genes determined on a gene map?