Question

explain point wise Origin of mutation plz .....Ans. fastly!!!!

Answer 1

Origin of the mutation

In 1996, following on from the outbreak of the Creutzfeldt-Jakob (“mad cow”) disease, the European Union launched systems for monitoring the prionic group of illnesses — the group to which FFI belongs. It was only then that the high rate of carriers of the mutation (D178N) responsible for FFI was detected in the Basque Country Autonomous Community (with 50% of all cases registered in Spain).

The area is characterised by its mountainous orography, and which has favoured cultural and genetic isolation. These features caused researchers to think that there might be a ‘founder effect’ of the mutation in the Basque Country — ‘founder effect’ is when a new population of individuals is formed from a very small number, with a large proportion thereof carrying the same genetic characteristics.

Given this situation, three targets were set: to look for the possible founder effect of the D178N mutation amongst patients in the Basque Country; establish relations between carriers in the Basque Country with other cases in Spain and Europe; and fix the historical time of the most recent common ancestor.

Same genetic families

After studying cases of FFI in the Basque Country, the researcher observed that genetic families amongst the patients coincided with each other. She concluded, thus, that the high rate of the disorder is due to a ‘founder effect’ of the mutation in this geographical area. Moreover, genealogical data link most of the cases and fix the oldest mutation carrier generations in an area in the south of the Basque Country in the XVII and XVIII centuries.

In comparison with other regions, Dr. Rodríguez concluded that links can be established between cases in Germany and those of the Italian Veneto region, on the one hand; between Italians of Tuscany and some Spanish cases, on the other; and that not all Spanish cases have the same origin. On estimating the age of the most recent common ancestor, they were able to calculate that two of these variants of the mutation arose over 2,000 years ago.