Warmup Cells created by mitosis are called diploid, while cells created by meiosis are called haploid. Try to guess the meaning of these vocabulary words using what you know about cell reproduction. Work in a group if you get stuck.
OCTOBER 7, 2010
Essential Standards Students understand the relationships between DNA, genes, chromosomes, alleles, and traits. Learning Objectives
Vocabulary Allele: The specific version of a gene. Trait: A characteristic manifested because of a combination of alleles.
Vocabulary Dominant: Allele that ‘wins’ a tie and show up in Phenotype. Recessive: Allele that ‘loses’ a tie against another allele. Co-dominant: Neither one type nor the other is overpowering, true tie. Genotype: How your genes are setup. Phenotype: What traits appear because of your genotype. Heterozygous: One of each alleles. Homozygous: Two of the same alleles.
Alleles Alleles are represented with capital (dominant), lowercase (recessive) letters. You can map out all possible genotypes, and assign them a phenotype. GenotypePhenotype AA (homogeneous dominant)Dominant Aa (heterogeneous dominant)Dominant aa (homogeneous recessive)Recessive Aa(co-dominant)Co-dominant
Punnit Squares ParentsAA aAa a In a Punnit Square, you write on parent’s alleles across one side, the second parent’s alleles across the other side, and then use the interior boxes to determine all possible combinations of the offspring’s alleles. When you are finished, you determine the probability of each outcome. Probability is the chance of the outcome divided by the total number of outcomes. Ex: Parents are aa and AA 100% chance of a heterozygous recessive outcome (Aa).
Punnit Squares Example 2 ParentsAA AAA aAa Ex: Parents are AA and Aa 50% chance of a homogeneous dominant outcome (AA). 50% chance of a heterozygous outcome (Aa).
Punnit Squares Example 3 ParentsAa AAAAa a aa Ex: Parents are both heterozygous 25% chance of a homogeneous dominant outcome (AA). 50% chance of a heterozygous outcome (Aa). 25% chance of homozygous recessive outcome (aa)