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Human Genetics

Description: This test will help the learning aspirants in preparing themselves in a better way for their exams.
Number of Questions: 15
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Tags: Genes translocation DNA Finger Printing DNA Replication Gene Expression and Regulation Regulation of Gene Expression
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Which of the following statements regarding DNA footprinting procedure is incorrect?

  1. DNA fragment thought to contain protein binding sequence is extracted, amplified and labelled at both the ends of DNA.

  2. Protein has protected the DNA binding site from cleavage agent.

  3. DNA fragments are separated by polyacrylamide gel electrophoresis.

  4. The missing band indicates the protein binding specific DNA sequence.

  5. The labelled DNA fragments are mixed with cleavage agents without DNA binding protein.


Correct Option: A
Explanation:

This statement is incorrect, hence the right answer. DNA fragment thought to contain protein binding sequence is extracted, amplified and labelled at one end of the double helix using polymerase chain reaction technique.

The pseudogenes can interfere with the PCR and in situ hybridisation experiments. Which of the following statements regarding the pseudogenes is FALSE?

  1. Exact mapping of the pseudogenes onto chromosomes is extremely difficult.

  2. The absolute rate of mutation is lower in nucleus than the one occurring in mitochondria.

  3. They form a molecular record of the evolutionary history and statistics of the parental genome.

  4. They are also useful to find the rate of nucleotide substitutions, DNA loss, etc.

  5. Multiple pseudogenes of the same sequence are found in human genes.


Correct Option: C
Explanation:

They form a molecular record of the evolutionary history and dynamics of the parental genome.

Which of the following markers used in DNA fingerprinting of plants show high level of polymorphism and are reproducible also?

  1. Sequence characterised amplified region (SCAR)

  2. Single Nucleotide Polymorphism (SNPs)

  3. Expressed Sequence Tags (ESTs)

  4. Inter-simple sequence repeat (ISSR)

  5. Minisatellites


Correct Option: E
Explanation:

Minisatellites consist of regions containing repeat sequences 16 to 64 base pairs. Different individuals have different number of repeats as mutation rate is high in these regions. Thus,  these markers show high level of polymorphism and are reproducible also.

A vast range of specific protein-DNA interactions occur due to the unique and major motifs. Which of the following listed motifs includes lactose repressors and cyclic AMP catabolite activator protein?

  1. Leucine Zipper Motif

  2. Zinc Finger Motif

  3. Helix-Turn-Helix Motif

  4. Helix-Loop-Helix Motif

  5. BLAST


Correct Option: C
Explanation:

Helix motif proteins include lactose repressors and cyclic AMP catabolite activator protein or CAP of E.coli,  and several developmentally important transcription factors in mammals, collectively referred to as homeodomain proteins. Homeodomain proteins play a major role in development of mammals.

A single nucleotide polymorphism is a variation, at a single position in a DNA sequence among individuals. Which of the following techniques of epigenetics is used to find the single nucleotide polymorphism?

  1. Direct sequencing

  2. Pyrosequencing

  3. Methylation-sensitive single-strand conformation analysis (MS-SSCA)

  4. High resolution melting analysis (HRM)

  5. Methylation-sensitive single-nucleotide primer extension (MS-SnuPE)


Correct Option: D
Explanation:

High-resolution melting analysis (HRM) is used to find the single nucleotide polymorphism. The method is based on the technique of real time PCR. The extent of DNA methyaltion is calculated from the C : T ratio as determined by changes in temperature and subsequent release of the fluorescent dye.

In which of the folowing mutations the two chromosomes interchange their chromosome segments leading to certain disorders?

  1. Translocations

  2. Duplications

  3. Inversions

  4. Deletion

  5. Aneuploidy


Correct Option: A
Explanation:

This type of mutation takes place between two chromosomes and interchanges their chromosome segments. In other words, a portion of chromosome is transferred on to other chromosome.

The novel coronary artery disease risk gene loci, mainly comprises of the following chromosomes, GenevZNF259 communicates mitogenic signals from the cytoplasm to the nucleus. It is associated with

  1. Chromosome 1p32.2

  2. Chromosome 7q32.3

  3. Chromosome 9q34.2

  4. Chromosome 11q23.3

  5. Chromosome 15q25.1


Correct Option: D
Explanation:

ZNF259 where the gene ZNF259 plays an important role as a signaling molecule. ZNF259 communicates mitogenic signals from the cytoplasm to the nucleus and interacts with tyrosine kinase receptors.

Which of the following statements does NOT characterise RNA editing in both plants and animals?

  1. After editing, all amino acids at the number 228 position are converted to cysteine.

  2. The RNA editing events occur at random in the transcript.

  3. The primary benefit of RNA editing could be evolutionary conservation of protein structure.

  4. Plant mitochondria do not use the universal genetic code.

  5. Editing converts a tryptophan codon to methionine codon.


Correct Option: E
Explanation:

Structural RNAs such as tRNAs and rRNAs are also affected. Editing can convert a tryptophan codon to arginine codon (CGG to UGG).

Which of the following genetic disorders occurs due to the swapping over of genetic material between chromosomes?

  1. 46, XX

  2. 48, XXYY syndrome

  3. 47, XYY syndrome

  4. Y chromosome infertility

  5. 47, XXY


Correct Option: A
Explanation:

This state results from an abnormal swap over of genetic material between chromosomes. This swap over occurs as a chance event in the father of an affected person during the formation of sperm cells. The translocation affects the gene in charge that is SRY for development of a fetus into a male. 

Which of the following genetic disorders is expressed in heterozygotic condition in humans?

  1. Congenital Ichthyosis

  2. Cystic Fibrosis

  3. Tay-Sachs Disease

  4. Brachydactyly

  5. Sickle Cell Anemia


Correct Option: D
Explanation:

A genetic state in which the fingers are unusually short in heterozygotic condition. But, this condition is lethal during early years to homozygous recessive individuals due to major skeletal defects .

There are certain mechanisms involved in the origin of new genes. Which of the following mechanisms occurs between the genomes of the cell organelles like mitochondria, chloroplasts and nuclear genomes?

  1. Gene duplication

  2. De Novo Gene Origination

  3. Gene Fusion and Fison

  4. Transposable Element(TE) protein domestication

  5. Lateral Gene Transfer


Correct Option: E
Explanation:

It is referred to the situation in which a gene does not have a vertical origin (that is direct inheritance from parent to offspring), but comes from an unrelated genome. It is recognised that this type of transfer occurs between bacteria and has taken place between the genomes of the cell organelles like mitochondria, chloroplasts and nuclear genomes.

Which of the following types of mutagenesis is used to introduce multiple mutations into the DNA sequence?

  1. Directed Mutagenesis

  2. Random Mutagenesis

  3. Mismatched Mutagenesis

  4. Cassette Mutagenesis

  5. PCR Mutagenesis


Correct Option: D
Explanation:

Is used to introduce multiple mutations into the DNA sequence. Using blunt ended DNA at the site of mutation, a 3 base pair direct terminal repeat is created. The mutagenic codon cassette has a head to head SAPL site to remove all the DNA except the mutated one.

Which of the following are derived from hybridisation of parents with dissimilar genomic sets?

  1. Autoallopolyploids

  2. Complete allopolyploids

  3. Segmental allopolyploidy

  4. True polyploids

  5. Neopolyploids


Correct Option: D
Explanation:

True or genomic polyploids are derived from hybridisation of parents with dissimilar genome sets.

There are numerous types of genetic markers. Which of the following has been used to trace the phylogeny of different organisms?

  1. Variable Number Tandem Repeat or VNTR

  2. Single Nucleotide Polymorphism or SNP

  3. Random Amplification of Polymorphic DNA or RAPD

  4. Amplified Fragment Length Polymorphism or AFLP

  5. Short Tandem Repeat or STR


Correct Option: C
Explanation:

It is a type of polymerase chain reaction but in this case DNA segments that are amplified would be random. It has been used to trace the phylogeny (is the sequence of events involved in the evolutionary development of a species or taxonomic group of organisms) of various animals and plants.

DNA damage caused by exogenous agents comes in various forms. Which of the following agents increases the rate of depurination in DNA strands?

  1. UV-B light

  2. UV-A light

  3. Vinyl chloride

  4. Ionising radiation

  5. High tempretures


Correct Option: E
Explanation:

Thermal disruption at elevated temperature increases the rate of depurination (loss of purine bases from the DNA backbone) and single-strand breaks. For example, hydrolytic depurination is seen in the thermophilic bacteria, which grows in hot springs at 40-80 °C.

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