In a certain species of prickly pear, having straight or curved spines is a trai
ID: 185662 • Letter: I
Question
In a certain species of prickly pear, having straight or curved spines is a trait controlled by genes at a single locus, with the straight spine allele dominant to the curved spine allele. A population of prickly pears has 37 individuals with straight spines and 42 individuals with curved spines. Of the prickly pears with straight spines, 26 have a homozygous dominant genotype. Is this population in equilibrium? Calculate p and q from the number of individuals of each genotype: p = _____ q = _____ Calculate the expected frequency of each genotype if the population is in equilibrium: _____ = Frequency of homozygous dominant individuals _____ = Frequency of heterozygous individuals _____ = Frequency of homozygous recessive individuals Calculate the expected number of individuals of each genotype in a population of 79 prickly pear cacti if the gene is in equilibrium: _____ = Number of homozygous dominant individuals _____ = Number of heterozygous individuals _____ = Number of homozygous recessive individuals Test how well your data fits the expected values from the equilibrium model: _____ Chi-square test statistic ______ P value _____ (y/n) in equilibrium?
Explanation / Answer
Total population = 37+42 = 79
1.p= 37/79 = 0.468
2.q= 42/79 = 0.531
3.Expected frequency = 37*42 / 79 = 19.67
from straight spines homozygous = 26, heterozygous = 11
from curved spines homozygous = 30 heterozygous = 12
calculating chi square value test = 0.0128 p value = 0.9099
The result is not significant at 95% confidence interval.