What are the genotypes for different flower colors in a monohybrid cross?

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SUMMARY

The discussion centers on determining the genotypes associated with flower colors resulting from a monohybrid cross of plants with green flowers. The offspring ratio of 36 green, 23 black, and 21 blue suggests a 1:2:1 ratio, indicative of a Gg x Gg cross. The genotypes are identified as 1 GG, 2 Gg, and 1 gg. The conversation explores the concepts of codominance and incomplete dominance, concluding that the presence of specific alleles influences the flower color phenotype, with homozygous individuals exhibiting a default color due to molecular interactions.

PREREQUISITES
  • Understanding of Mendelian genetics, specifically monohybrid crosses
  • Familiarity with the Law of Segregation and Law of Independent Assortment
  • Knowledge of genotype-phenotype relationships in genetics
  • Basic concepts of codominance and incomplete dominance
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  • Research the implications of codominance and incomplete dominance in plant genetics
  • Study the molecular mechanisms behind allele interactions in flower color determination
  • Explore the concept of overdominance and its effects on phenotype expression
  • Investigate the role of mutations in altering flower color phenotypes
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Students studying genetics, plant biologists, and educators looking to deepen their understanding of inheritance patterns and flower color genetics.

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Homework Statement



A cross between two plants that both have green flowers produces 80 offspring plants, of which 36 have green flowers, 23 have black flowers, and 21 have blue flowers. Color variation is due to inheritance at one locus. What is the genotype associated with each flower color?

How can the inheritance of the flower color be described?

Homework Equations



Law of Independent Assortment
Law of Segregation

The Attempt at a Solution



36/80 green
23/80 black
21/80 blue

such numbers yield a ratio close to 1:2:1, equivalent to a monohybrid cross.

Gg x Gg

1 GG
2 Gg
1 gg

This seems to indicate either codominance or incomplete dominance. However, in this case, the hybrids are neither a blend of their parents nor do they exhibit traits from both parents, so I'm left a little confused.

Do I need to somehow incorporate mutations or wild type into this?
 
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Hello!
From Scitable, Genetic Dominance: Genotype-Phenotype Relationships, under the overdominance section:

"In some instances, offspring can demonstrate a phenotype that is outside the range defined by both parents."

It's difficult to think of a scenario that is plausible for the phenotpye of heterozygotes. Perhaps one does not dtermine colour without the presence of the other allele. Homozygous individuals in this case may have a 'default' colour due to the presence of a molecule, A. One allele may convert A to B, and the other allele B to C. Without the allele converting A to B, the allele for B to C will not perform its function, the flower will then have the default colour in individuals homozygous for this allele. Homozygous individuals for the the other allele, will convert A to B, producing a certain colour; and heterozygous individuals will convert A to B and B to C, producing yet another colour (in this case, green). This seems plausible, but I'm not sure if it is what you are looking for.
 
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