Stubble Bristle (or other recessive lethal)

Exercise for Dr. M. B. Gardner's GN 412 Course

Watch the changes in phenotype and gene frequencies

Enter h with decimal point:               Fitnesses are:   ++ : 1       +Sb : 1-h       SbSb : 0
To get a good quality graph after you've plotted this graph, go to the "Good Graph" button below all the frequencies and click it - there will be short wait for the graph.
.9-1
.8-.9
.7-.8
.6-.7
.5-.6
.4-.5
.3-.4
.2-.3
.1-.2
0-.1
Gen 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
++
+Sb
SbSb
+
Sb
      Use your browser's Back and Forward buttons to compare that graph and the data above.
Notes: This experiment starts with monohybrid cross, +Sb x +Sb. Therefore p(0) = q(o) = 1/2, in the eggs produced by this monohybrid cross. This generation is not shown above, but it undergoes selection and random mating to produce the Generation 1 shown above, and similarly for succeeding generations.

The frequency of the recessive homozygotes (SbSb) shown for each generation is the frequency at fertilization (i.e. in the eggs.) Each generation is produced by random mating of the adults in the previous generation.

To allow a more compact representation, the "Sb" gene is represented by the "S" symbol in the display boxes. Also, if more than one genotype falls in a display box, only the last one (in the order ++, +S, SS) is shown. This can easily be seen by checking the numerical frequency values for the genotypes each generation.
Please send comments to hes@ncsu.edu   --henry schaffer

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Copyright © 1999, 2000 by Henry E. Schaffer       Last modified: 1/31/00