MENDELIAN SEGREGATION 25 
chromosomes as readily as one or two. It will not 
be necessary to give the full analysis, for it will be 
easily understood from the scheme already given. 
If a fly with vestigial wings is crossed to an ebony, 
eyeless fly three pairs of factors are involved that lie 
in different chromosomes. The F, flies are normal, 
for there is in the hybrid a normal mate for each of 
the three recessive factors. The possible recombina- 
tions are shown in the next diagram, Fig. 13. There 
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Fig. 13.—Diagram to show the segregation of the three pairs of chro- 
mosomes. Eight combinations are possible, giving 8 kinds of germ cells, 
with 64 possible re-combinations. 
are four different positions for the chromosome pairs 
on the spindle, leading to eight kinds of germ cells. 
By chance meetings of the eight kinds of sperm with 
the eight kinds of eggs there will result 8 types as 
follows: 
27 Long, gray, normal eye (wild type). 
9 Vestigial, gray, normal eye. 
9 Long, ebony, normal eye. 
9 Long, gray, eyeless. 
3 Vestigial, ebony, normal eye. 
3 Vestigial, gray, eyeless. 
3 Long, ebony, eyeless. 
1 Vestigial, ebony, eyeless. 
