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

  • Thread starter Thread starter Foghorn
  • Start date Start date
  • Tags Tags
    Genetics
AI Thread Summary
The discussion centers on determining the genotypes for flower colors resulting from a monohybrid cross between 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 confusion arises from the lack of clear codominance or incomplete dominance, as the hybrids do not show traits from both parents. The conversation explores the possibility of mutations or wild types influencing flower color, proposing that specific alleles may interact to produce distinct colors. The complexity of genotype-phenotype relationships in this context highlights the need for further clarification on inheritance patterns.
Foghorn
Messages
7
Reaction score
0

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?
 
Physics news on Phys.org
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.
 
Last edited:
Thread 'Confusion regarding a chemical kinetics problem'
TL;DR Summary: cannot find out error in solution proposed. [![question with rate laws][1]][1] Now the rate law for the reaction (i.e reaction rate) can be written as: $$ R= k[N_2O_5] $$ my main question is, WHAT is this reaction equal to? what I mean here is, whether $$k[N_2O_5]= -d[N_2O_5]/dt$$ or is it $$k[N_2O_5]= -1/2 \frac{d}{dt} [N_2O_5] $$ ? The latter seems to be more apt, as the reaction rate must be -1/2 (disappearance rate of N2O5), which adheres to the stoichiometry of the...
Back
Top