Question

A bacterium was found to contain a sequence of ATCGGGATCCT in its genome. A few generations later, the sequence was found to be ATCGGGGGGATCCT. What type of mutation caused this change in the bacteria?
A.
duplication
B.
insertion
C.
inversion
D.
translocation

Answer 1

Answer:

duplication  

Explanation:

• Inversion

If we talk about inversion, it inversion, it is a process in which a specific base sequence is inverted or rearranged in such a way that direction is reversed. For example: ABC is changed into BCA, therefore it is not right option.

• Translocation

If we talk about translocation,it is  caused by rearrangement of parts between non homologous chromosomes. It can be balanced or unbalanced but it involves two genes or two sets of chromosomes. But in our example, we have only one sequence of DNA under study, therefore, inversion is not possible.

• Insertion

Talking about insertion, it involves addition of one or more nucleotide at certain position of gene sequence. There are chances that it can be an insertion of GGG but the insertion of three G instead of any random nucleotide addition or nucleotide sequence addition is rare. So, there are less chances that this is an insertion and more chances that this is an exact duplication event.

• Duplication:

If we talk about duplication, a certain portion of a gene or chromosome is  replicated or duplicated in such a way that it results in more than one copies of that region.

Keeping that definition infront, we see that GGG duplicated to GGGGGG.  So, if we logically look at the question, duplication seems to be the most appropriate option.

Hope it help!