The following schematic shows the region of a gene associate

The following schematic shows the region of a gene associated with hairy toes (HTO). The hairy toes phenotype is due to recessive mutations which create an RFLP within a HaeIII restriction site at position 550 (HaeIII sites are indicated by arrows). Note that there may be other snp, but these are unrelated to the phenotype of hairy toes. This region of the genome was examined in different individuals by performing a Southern analysis on genomic DNA samples digested with HaeIII and probed with a DNA fragment spanning the region from 425-650. The results of the hybridization are shown in the table below.

a) Which individual (s) have a genotype which would give them the hairy toes phenotype?
b) Which individual (s) have a genotype which would give them the normal phenotype?
c) Which individual (s) is (are) a carrier of the hairy toes genotype, but have a normal phenotype?
d) How many different alleles of the region were detected among the four individuals?

PLEASE ANSWER ALL QUESTIONS AND EXPLAIN I WANT TO UNDERSTAND!

75 10 550 250 700 Individual Sizes of bands observed (bp) dA 450 and 625 475, 300 and 150 B C 300 and 150 D 475, 450 and 150 1075

Solution

Southern blotting has many applications in molecular biology,including the identification of one or more restriction fragments that contain a gene or other DNA sequence of interest ,and in the detection of RFLPs used in construction of genomic maps. If the probe DNA finds a homologous sequence in the blot, it base-pairs (\"hybridizes\") to that DNA. The radioactivity then exposes the film and produces a dark band on the X-ray film.

Southern analysis on genomic DNA samples digested with HaeIII and probed with a DNA fragment spanning the region from 425-650

1) Individual A has both the bands with 425-650 range this will have a hairy toes phenotype.

2) B and C and D will have normal phenotype because the base pairs does not fall under the range of 425-650

3) D and B will have genotype of hairy toes but will have a normal phenotype.

4) Three differenet alleles at the position of 450,475 and 625 are detected through this analysis among four individuals.