:1 asked in Science & MathematicsBiology · 1 month ago

Genetics Based Question - HW equation and Chi square?

An Angus stud breeder in Wagga has been selecting animals for improved marbling, and wants to find out whether he has inadvertently selected for this newly reported mutant. Accordingly, he genotypes animals for this mutant, and finds 200 cattle homozygous for the superior marbling allele (MM), 200 to be heterozygous (Mm), and another 100 to be homozygous wild-type (mm). You are a breeding consultant, and the stud breeder brings you this data for advice.

1. derive expectations (Explain how expectations have been derived)

2.  chi-square test (Show all working steps)

1 Answer

Relevance
  • 1 month ago
    Favourite answer

    Answer:

    200 MM = 2 * 200 = 400 “M” alleles

    100 mm = 200 “N” alleles

    Mm 200 = 200 “M” and 200“m” alleles

    Total alleles = 1000

    Frequency of “M” allele = 400+200 /1000 = 0.6

    Frequency of “m” allele = 200+200/1000 = 0.4

    Three expected genotypes are produced as follows.

    Total population = 500

    Frequency of genotype, MM = 0.6*0.6 = 0.36

    MM individuals = 0.36 * 500 = 180

    Frequency of genotype, mm = 0.4*0.4 = 0.16

    mm individuals = 0.16 * 500 = 80

    Frequency of genotype, Mm = 2* 0.6 * 0.4 = 0.48

    Mm individuals = 0.48 * 500 = 240

    Phenotype    Observed(O) Expected (E)  O-E ( O-E)2  (O-E)2/E

    MM                200               180                 20       400        2.222

    Mm                200                 80               120      14400      180.000

    mm                100               240                -140   19600.00    81.6667

                           500               500                                             263.8889

    Chi-square value = 263.89

    Degrees of freedom = number of categories – 1

    Df = 3-1 = 2

    Critical value = 5.99

    The chi-square value of 263.89 is greater than the critical value of 5.99. So we can reject the null hypothesis. Hence the population is not in Hardy-Weinberg equilibrium

    please rate!!

Still have questions? Get answers by asking now.