Question

Question Regarding RFLP marker

I have an RFLP marker for a family with 2 parents and 4 children. The gender of the parents are not told

1. Child 1 has 3 bands, how to determine if that child has trisomy of the chromosome due to a non-disjunction during Meiosis II or Meiosis I and how to tell which parents gametes caused this parent 1 or parent 2.

2. How to determine which of the children is a half sibling with only 1 biological parent

3. Child # 4 is missing information, how to tell which information that child is missing

Answer 1

During RFLP analysis, the restricted fragments length is analysed according to their passing through the gel matrix in electrophoresis. The number and size of the restricted fragment of the children are analysed in correspondence with the restriction fragments of the parents.

1. The child 1 has three bands when the sample of the DNA fragments are put under electrophoresis. The careful study should be done to check the corresponding bands in the parent's DNA fragments. The parent with whose RFLP bands are similar with the two of the child is the cause of trisomy. Due to unsaggregation, the chromosomes of that parent are not separated properly.

2. The child whose rflp fragments are not showing any correspondence with one of the parent is the half sibling or we can say that the the child has only one biological parent with whose the rflp fragments show similar bands.

3. The missing information in the the rflp band of the child 4 is can be determined by observing the missing fragments in correspondence to the rflp fragments of both the parents. In other words, we can say that the child has no any restricted fragment in correspondence with any of the restricted fragments of the two parents. That chromosome or DNA portion is missing.