Sequence Homology in Molecular Genetics

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What is the primary purpose of analyzing sequence homology between different species?

To construct phylogenetic trees and classify organisms (correct)

To study the structure and function of individual proteins

To identify gene duplication events within a single species

To compare the evolution of different hemoglobin variants

Which of the following terms refers to similar sequences that have diverged within the same species due to gene duplication?

Homologs

Orthologs

Analogs

Paralogs (correct)

If hemoglobin A and hemoglobin B are paralogs, what can be inferred about their relationship?

They are unrelated sequences with no evolutionary connection

They are found in the same species and arose from a gene duplication event (correct)

They are different variants of hemoglobin found in different tissues of the same organism

They are found in different species and evolved from a common ancestor

Which type of paralogs are genes or sequences that have duplicated after the last speciation event?

Sym-paralogs Signup and view all the answers

Which term describes genes or sequences that have duplicated before the last speciation event?

Allo-paralogs Signup and view all the answers

If two sequences are identified as orthologs, what can be inferred about their relationship?

They are homologous sequences found in different species that evolved from a common ancestor Signup and view all the answers

Which of the following sequences are the result of gene duplication events?

Paralogs Signup and view all the answers

Which type of sequences share a common ancestral sequence between distantly related organisms?

Xenologs Signup and view all the answers

Which of the following sequences have similar structure or function but do not share a common ancestral sequence?

Analogs Signup and view all the answers

What is the ultimate goal of sequence alignment in bioinformatics?

To determine the similarity between different sequences Signup and view all the answers

Which of the following sequences can be used for alignment in bioinformatics?

All of the above Signup and view all the answers

What is the definition of an alignment in bioinformatics?

An arrangement of two or more related sequences in a successive order Signup and view all the answers

What is the gap opening penalty used in the text?

-5 Signup and view all the answers

What is the gap extension penalty used in the text?

-1 Signup and view all the answers

Why would a mismatch be better than adding gaps in both sequences according to the text?

Alignment does not make sense when both deletion and insertion occur Signup and view all the answers

What is the total score for the alignment presented in the text?

32 Signup and view all the answers

Which amino acid is represented by the letter 'P' in the BLOSUM62 scoring matrix shown in the text?

Proline Signup and view all the answers

Which amino acid is represented by the letter 'I' in the BLOSUM62 scoring matrix shown in the text?

Isoleucine Signup and view all the answers

What is the difference between identity and similarity for protein sequences?

Identity refers to the percentage of exact matches between aligned sequences, while similarity refers to the percentage of aligned residues that share similar characteristics. Signup and view all the answers

Which of the following is NOT a characteristic used to classify proteins?

Hydrophilic Signup and view all the answers

If sequence A is identical to sequence B, and sequence B is identical to sequence C, does it necessarily mean that sequence A is identical to sequence C?

No, even if A is identical to B and B is identical to C, A may not be identical to C. Signup and view all the answers

What does the term 'identity' refer to in the context of nucleotide sequences (DNA & RNA)?

The percentage of exact matches between two aligned sequences. Signup and view all the answers

If sequence A is 85% identical to sequence C, what can be inferred about the relationship between sequences A, B, and C?

No inference can be made about the relationship between sequences A, B, and C. Signup and view all the answers

Which of the following statements is true?

The terms 'identity' and 'similarity' have different meanings for both nucleotide and protein sequences. Signup and view all the answers

What is one of the reasons provided in the text for conducting sequence alignment?

Identifying homologous genes Signup and view all the answers

What is the significance of a good alignment between a gene from another organism and an open reading frame (ORF)?

There is strong evidence that the ORF is a gene Signup and view all the answers

What technique can be used to estimate the probability of an open reading frame (ORF) actually constituting a gene?

Gene prediction algorithms Signup and view all the answers

In the context provided, what is a key application of gene finding?

Predicting gene locations Signup and view all the answers

How can sequence alignment aid in function prediction according to the text?

By identifying homologous genes Signup and view all the answers

What aspect of genome analysis involves using alignments to assemble genome sequences?

Genome Sequence Assembly Signup and view all the answers