What evidence do you think is the most reliable and conclusive for determining common ancestry. Explain why you think this is.

Question

1. 1 point for complete sentences
2. 1 point clearly identifies the piece of evidance
3. 1 point for clear explanantion.

Answer 1

In the case of consanguineous parents, it is possible to assume that mutations are homozygous and has been inherited within a chromosome present in the common ancestor. Successive recombinations alter the ancestral chromosome in each parent, so that they will pass on to the offspring two chromosomes that are not completely homozygous but do present large stretches of homozygosity which are very likely to contain the causative mutation. It is possible to map such regions independently or using data derived exclusively from whole-exome sequencing, simply by detecting areas in which all novel and known polymorphisms are homozygous. Such mapping allows to discard all variations which are homozygous by chance rather than by common ancestry.