Hardy Weinberg Principle: Calculating Allele Frequency in a Fish Population

  • Thread starter Thread starter xChee
  • Start date Start date
  • Tags Tags
    Weinberg
Click For Summary

Discussion Overview

The discussion revolves around applying the Hardy-Weinberg principle to calculate allele frequencies in a fish population, specifically focusing on the dominant and recessive alleles associated with eye color. The context is a homework problem involving the interpretation of allele frequencies based on observed phenotypic ratios.

Discussion Character

  • Homework-related, Mathematical reasoning

Main Points Raised

  • One participant presents a calculation attempt for the frequency of the red allele, suggesting a value of 96.67% based on the number of fish with red eyes.
  • Another participant questions the validity of this calculation, indicating that the fraction of the population with red eyes (40 out of 300) does not directly equate to the frequency of the dominant allele (p).
  • There is a suggestion to express the fraction of the population with blue eyes in terms of the recessive allele frequency (q), which could simplify the calculations.
  • A later reply acknowledges the previous point about expressing blue eye frequency in terms of q, indicating a shift in approach from the initial attempt.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on the correct approach to calculating the allele frequencies, with multiple viewpoints and methods being discussed.

Contextual Notes

There are limitations in the initial calculations, particularly regarding the assumptions made about the relationship between phenotype and allele frequency. The discussion highlights the need for clearer definitions and expressions of the population fractions in terms of p and q.

xChee
Messages
15
Reaction score
0

Homework Statement



In a population on fish, 40 have red eyes and 260 have blue eyes. Allele for red is dominant over blue alleles. Use hardy Weinberg principle to calculate the frequency of the white and red allele.

Homework Equations



p2 + 2pq + q2 = 1

q + p = 1

The Attempt at a Solution



p = 96.67 %

i took 40 and divided it by 300 and for 13.3% as my answer. but i got it wrong...I'm pretty much stuck, help?
 
Physics news on Phys.org
Assuming p is the frequency of the dominant allele, can you use p & q to express what fraction of the population has red eyes?

Note: \frac{40}{300} is the fraction of the population with red eyes, but it is not equal to p.
 
It is also helpful is to express the fraction of the population that has blue eyes in terms of q.
 
Ygggdrasil said:
It is also helpful is to express the fraction of the population that has blue eyes in terms of q.

Good point. Much simpler than what I attempted to do.
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 2 ·
Replies
2
Views
16K
Replies
12
Views
4K
Replies
1
Views
5K
  • · Replies 4 ·
Replies
4
Views
4K
  • · Replies 4 ·
Replies
4
Views
6K
Replies
1
Views
5K
Replies
3
Views
3K
  • · Replies 1 ·
Replies
1
Views
404