Consider seven recessive genes, a, e, d, j, l, y and r. The seven loci are closely linked in the centromeric region of an autosome but their order is unknown. Six deletions are examined in an individual that is heterozygous for all seven genes. All six deletions resulted in pseudodominance of at least two genes, and two deletions spanned the region of the centromere. Deletion Centromere included in deletion Genes exhibiting pseudodominance del 1 No e and j del 2 Yes a, l and r del 3 No a and d del 4 Yes e, l and r del 5 No d and y del 6 No e and l Determine the gene order and the location of the centromere.