a. Measurement error,
e. Supercoiled linear fragments.
The DNA length in the band of the agarose gel is measured by comparing it with the bands of the DNA ladder. This is a very less efficient method which can incorporate error in the measured data. Moreover, if the DNA is supercoiled, it will be highly packed and can run in the gel in a much faster rate than the actual linear fragment which will again introduce error in size determination.
The fragment sizes that you determined from your gel may not be exactly correct (i.e. they...
2. A dominant allele H reduces the number of body bristles that Drosophila flies have, giving rise to a “hairless” phenotype. In the homozygous condition, H is lethal. An independently assorting dominant allele S has no effect on bristle number except in the presence of H, in which case a single dose of S suppresses the hairless phenotype, thus restoring the "hairy" phenotype. However, S also is lethal in the homozygous (S/S) condition. What ratio of hairy to hairless flies...