Purple=dominant
White=recessive
5) After looking at the punnett square and using the vocabulary terms above, why were all the offspring in the F1 generation showing the dominant characteristic? Each trait is being controlled by genes. There is one packet that comes from each parent. When TT is crossbred with tt plants, they produce Tt plants in the F1 generation. The F1 plants are all purple because the T allele is expressed in every offspring and it covered up the t allele.
6) Any time you have a capital letter in one or both alleles, the dominant form of the trait is expressed. Only when you have both alleles as lower case letters does the recessive form of the trait expressed (Porteous 1). In the Punnett square above, do all of the offspring express the purple or white flowers? In the Punnett square above, all of the offspring express purple flowers because the T allele is dominant in all of the offspring. There is no allele that shows lower case letters so no recessive form of the trait is expressed. So there are no white flowers in F1 generation.
Use the offspring in the F1 generation to self-pollinate to create the parents of the F2 generation.
7) Explain how Punnett squares use the law of segregation. The punnett square is very useful in predicting the offspring of a genetic cross. The law of segregation states that all individuals have two alleles for every gene. So when gametes are formed through meiosis, the two alleles separate from each other and result to a gamete that has only one allele of each gene. This is known as Mendel’s first law of inheritance. Basically, the punnett square helps in determining the cross.
8) Use the punnett square above to answer the questions below?
All possible genotypes? Three out of four crosses have allele for yellow seed. The first one is a purebred yellow, the other two are heterozygous yellow, while the 4th cross phenotypically is a purebred green seed.
All possible phenotypes? Three out of four crosses have allele for yellow seed. The first one is a purebred yellow, the other two are heterozygous yellow, while the 4th cross phenotypically is a purebred green seed.
B 9) Mendel crossed dominant tall plants with tall plants. The results in the F1 generation were 84 tall plants and 29 recessive short plants.
D 10) Mendel crossed dominant axial flower position plants with recessive terminal flower position plants. The results in the F1 generation were 15 axial flower plants and 17 terminal flower plants.
A11) Mendel crossed dominant green pod plants with recessive yellow pod plants. The results in the F1 generation were 40 green pod plants and 0 yellow pod plants.
C12) Mendel crossed dominant smooth pod plants with smooth pod plants. The results in the F1 generation were 206 purple flower plans and 197 white flower plants.
D13) Mendel crossed dominant purple flower plants with recessive white flower plants. The results in the F1 generation were 206 purple flower plans and 197 white flower plants.
B14) Mendel crossed dominant gray seed coat plants with dominant gray seed coat plants. The results in the F1 generation had a ratio of 3 gray coat plants to every one recessive white seed coat plants.
C15) Mendel crossed dominant yellow seed plans with dominant yellow seed plants. The results in the F1 generation were all yellow seed plants and no recessive green seed plants. The results in the F2 generation were 714 yellow seed plants and 106 green seed plants.
A16) Mendel crossed dominant round seed plants with recessive wrinkled seed plants. The results in the F1 generation were all round seed plants and no wrinkled seed plants. The results in the F2 generation were 318 round seed plants and 121 wrinkled seed plants.
Works Cited
Porteous, John. (1996). Dominance one hundred and fifteen years after Mendel’s paper. Journal of Theoretical Biology. Vol 182 (3). 223-232.
