fa19 220 corn extra credit (1)

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Anne Arundel Community College *

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220

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Biology

Date

Feb 20, 2024

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docx

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1

Uploaded by nxlte

Name: Matthew Nolte Corn extra credit. Read the passage below (from the Carolina website) about the layers in corn kernels and what genes affect the phenotype of the layers. Worth up to 3 pts on your next exam. Kernel color Many genes determine the phenotypes of the 3 tissues that control the color of a corn kernel. These tissues are the pericarp, the aleurone (outer layer of the endosperm), and the endosperm proper. In our corn (meaning the corn we use in lab), the pericarp is always colorless, but the aleurone may be colorless, purple, or red, and the endosperm yellow or white. If the aleurone is colorless, the kernel color will be that of the endosperm, either yellow or white. Normal corn endosperm color (yellow) occurs when the allele Y causes the production of carotenoid pigments in the endosperm. In the recessive condition ( y/y ) carotenoids are not produced and the endosperm is white. The Y alleles are masked by the presence of a colored aleurone. Figure 1 The tissues of a corn kernel involved in producing color phenotypes. For the aleurone to be colored, alleles C and R must be present. The homozygous recessive of either allele ( c/c or r/r ) disrupts anthocyanin production and results in a colorless aleurone. The dominant C I allele also inhibits anthocyanin production, giving a colorless aleurone. Genes C and R are located on separate chromosomes and segregate independently. The allele Pr interacts with alleles C and R to produce a purple aleurone. The homozygous recessive condition ( pr/pr ) interacts with C and R to produce a red aleurone. Considering the monohybrid cross ear showing red and white kernels, determine what the genotype must be for each kernel color in terms of the pigmentation in the endosperm, pericarp and aleurone. Further, what must the genotype for Pr be in this corn? (in some instances, there are multiple answers) Red kernel - Endosperm: YY, Yy, or yy Aleurone: CC, Cc, RR, Rr, prpr Pericarp: colorless White kernel - Endosperm: yy Aleurone: cc, C I C I , C I C, C I c, rr Pericarp: colorless Purple kernel- Endosperm: YY, Yy, or yy Aleurone: CC, Cc, RR, Rr, PrPr, Prpr Pericarp: colorless Fa19 bio 220 corn lab extra credit Page 1
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