Supplemental Data TABLE 1
Viability Counts
A. Progeny from crossing cry0/TM6B to Df(3R)Dl-Bx12/MKRS
Df/TM6B
cry0/MKRS
cry0/Df
TM6B/MKRS
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Count
70
1210
898
467
Ratio
-
2.6
1.9
1.0
B. Control for A: cry+/TM6B x Df/MKRS
Df/TM6B
cry+/MKRS
cry+/Df
TM6B/MKRS
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Count
0
203
98
60
Ratio
-
3.4
1.6
1.0
C. Progeny from Mendelian test: cry0/cry+ x cry0/cry+
cry0/cry+
cry0/cry0
cry+/cry+
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Count
167
85
72
Ratio
2.3
1.2
1.0
For each of the three types of crosses, the lefthand parental genotype was carried in
females, the righthand one in males. With regard to A and B, the deletion (Df) of the cry
locus and the 3rd-chromosomal balancers (TM6B and MKRS) are specified in MATERIALS
AND METHODS;
the cry-null mutations were from the cry01 and cry02 strains (used in
separate crosses that led to the data in A), and the cry+ allele (B) was from the isoW
strain (see MATERIALS AND METHODS). The ratios involving progeny from A and B
crosses were computed with respect to numbers of balancer-over-balancer progeny set
equal to 1.0. These calculations ignored numbers of the Df/TM6 offspring (thus the “-”
entries), because flies of that doubly-defective genotype exhibited erratic and very low
adult-emergence probabilities overall. Putative reason: combined effects of
heterozygosity for this Df (a deletion that removes genes in addition to the cry one) and
the dominant marker contained in the TM6 balancer. Inferentially, other fly types
carrying this Df are have their viability impinged upon, irrespective of the cry allele
carried on the homologous 3rd chromosome; hence, the ratio method for computing
relative viabilities as affected by uncoverage of cry0 by this deletion, vis-à-vis
heterozygosity for the Df and cry+. That number for the cry0/Df offspring is clearly
robust in comparison to the cry+/Df control value. For cross C, the genetic background of
the parents was w1118; the three progeny types were scored by virtue of the w+-inserted
cry0’s leading to darker eye color in homozygotes compared with cry0/+ heterozygotes;
note that a classical F2 Mendelian ratio was realized; again, this indicates no deleterious
effect of the cry-null mutation on viability.