Three loci, mitochondrial malate dehydrogenase that forms a and b (MDHa, MDHb), glucouronidase that has forms 1 and 2 (GUS1, GUS2), and a histone gene that has + and - variants(H+, H-), are located on chromosome #7 in humans. Assume that the MDH locus is at position 35, GUS at position 45, and H at position 75. A female whose mother was homozygous for MDHa, GUS2, and H+ and whose father was homozygous for MDHb, GUS1, and H- produces a sample of 1000 egg cells. Give the genotypes and expected numbers of the various types of cells she would produce. Assume no chromosomal interference.© BrainMass Inc. brainmass.com March 4, 2021, 7:57 pm ad1c9bdddf
Since, the MDH locus is at position 35, GUS at position 45, and H at position 75, GUS is in between MDH & H.
Distance between MDH & GUS = 10 map unit
Distance between GUS & H = 30 map unit.
Since % recombinants = map distance
Hence, for gene MDHa & GUS2 locus :
10 = No. of recombinants for crossing over between MDHa & GUS2 / 1000 * 100
Or, No. of recombinants for crossing over between MDHa & GUS2 = 100