Questions and answers for exam Preparation

MCQs

Total Questions : 100 | Page 4 of 10 pages

Question 31. Which of the following is wrong statement about DNAML and DNAMLK?

PHYLIP includes mentioned two programs for this maximum likelihood analysis
DNAML estimates phylogenies from nucleotide sequences by the maximum likelihood method
DNAMLK estimates phylogenies in the same manner as DNAML
DNAMLK estimates phylogenies without molecular clock

Discuss Question

Answer: Option D. -> DNAMLK estimates phylogenies without molecular clock
Answer: (d).DNAMLK estimates phylogenies without molecular clock

Question 32. Which of the following is wrong statement about the maximum likelihood method’s steps?

It starts with an evolutionary model of sequence change that provides estimates of rates of substitution of one base for another
In the beginning there is an evolutionary model of sequence change that provides estimates of transitions and transversions in a set of nucleic acid sequences
The rates of all possible substitutions are chosen so that the base composition differs
The set of sequences is then aligned

Discuss Question

Answer: Option C. -> The rates of all possible substitutions are chosen so that the base composition differs
Answer: (c).The rates of all possible substitutions are chosen so that the base composition differs

Question 33. A method of sequence alignment based on a Model (Bishop and Thompson 1986) was introduced that predicts the manner in which DNA sequences change during evolution. Which of the following is wrong about it?

The basis of this method is to devise a scheme for introducing substitutions, insertions, and gaps into sequences
The basis of this method is to provide a probability that each of these changes occurs over certain periods of evolutionary time
Given each of these predicted changes, the method examines all the possible combinations of mutations to change one sequence into another
Multiple combinations are selected that will be the most likely over time

Discuss Question

Answer: Option D. -> Multiple combinations are selected that will be the most likely over time
Answer: (d).Multiple combinations are selected that will be the most likely over time

Question 34. Once all positions in the sequence alignment have been examined, the likelihoods given by each column in the alignment for each tree are _____ to give the likelihood of the tree.

multiplied
added
divided
squared

Discuss Question

Answer: Option A. -> multiplied
Answer: (a).multiplied

Question 35. A method of sequence alignment based on a Model (Bishop and Thompson 1986) was introduced that predicts the manner in which DNA sequences change during evolution. Which of the following is wrong about it?

This method is different from the Smith-Waterman local alignment algorithm
This method is quite similar to the Smith-Waterman local alignment algorithm
The underlying mutational theory is like those used to produce the PAM matrices for predicting changes in DNA and protein sequences
Sequences are predicted to change by a Markov process such that each mutation in the sequence is independent of previous mutations at that site or at other sites

Discuss Question

Answer: Option B. -> This method is quite similar to the Smith-Waterman local alignment algorithm
Answer: (b).This method is quite similar to the Smith-Waterman local alignment algorithm

Question 36. Which of the following is incorrect statement about the Kimura model?

It is a model to correct evolutionary distances and is a more sophisticated model
In this, the mutation rates for transitions and transversion are assumed to be different
According to this model, occur more frequently than transversions
According to this model, transversions occur more frequently than transitions

Discuss Question

Answer: Option D. -> According to this model, transversions occur more frequently than transitions
Answer: (d).According to this model, transversions occur more frequently than transitions

Question 37. The second step in phylogenetic analysis is to construct sequence alignment. This is probably the most critical step in the procedure because it establishes positional correspondence in evolution.

True
False
May be True or False
Can't say

Discuss Question

Answer: Option A. -> True
Answer: (a).True

Question 38. Which of the following is incorrect statement about Choosing Substitution Models?

There is one substitution at a particular position, in divergent sequences
The evolutionary divergence is beyond the ability of the statistical models to correct
The statistical models used to correct homoplasy are called substitution models or evolutionary models
For constructing DNA phylogenies, there are nucleotide substitution models available

Discuss Question

Answer: Option A. -> There is one substitution at a particular position, in divergent sequences
Answer: (a).There is one substitution at a particular position, in divergent sequences

Question 39. Which of the following is an incorrect statement?

In a phylogram, the branch lengths represent the amount of evolutionary divergence
Trees like cladogram are said to be scaled
The scaled trees have the advantage of showing both the evolutionary relationships and information about the relative divergence time of the branches
In a cladogram, the external taxa line up neatly in a row or column

Discuss Question

Answer: Option B. -> Trees like cladogram are said to be scaled
Answer: (b).Trees like cladogram are said to be scaled

Question 40. Which of the following is an incorrect statement about Newick Format?

It was designed to provide information of tree topology to computer programs without having to draw the tree itself
In this format, trees are represented by taxa excluded in nested parentheses
In this linear representation, each internal node is represented by a pair of parentheses
For a tree with scaled branch lengths, the branch lengths in arbitrary units are placed immediately after the name of the taxon separated by a colon

Discuss Question

Answer: Option B. -> In this format, trees are represented by taxa excluded in nested parentheses
Answer: (b).In this format, trees are represented by taxa excluded in nested parentheses