CBSE 2026 · Region 4 · Set 1 · Q32 · 5 marks
Write the types and locations of the genes causing thalassemia in humans. State the cause and symptoms of the disease. How is sickle-cell anemia different from this disease ?(b)Enlist any four prime goals of the Human Genome Project (HGP).(ii)List the two methodologies which were involved in the human genome project. Mention how they were used.(iii)Expand 'YAC' and mention what it was used for.
Write the types and locations of the genes causing thalassemia in humans. State the cause and symptoms of the disease. How is sickle-cell anemia different from this disease ?
(b)
Enlist any four prime goals of the Human Genome Project (HGP).
(ii)
List the two methodologies which were involved in the human genome project. Mention how they were used.
(iii)
Expand 'YAC' and mention what it was used for.
Marking-scheme solution
• Types and location of gene:
−α- Thalassemia is under the control of two genes HBA1 and HBA2 , both located on chromosome-$\displaystyle 16$
−β- Thalassemia is the control of a single gene HBB , present on chromosomes -$\displaystyle 11$
• Causes:
It is due to mutation / deletion of one or more of the four alleles of the genes controlling the disease.
• Symptoms:
Anaemia/ extreme tiredness / pale skin/ Breathlessness/ any other correct symptom
| Thalassemia | Sickle cell anaemia |
| It is quantitative where less amount of haemoglobin is synthesised. | It is qualitative where defective haemoglobin is synthesised. |
| Both α and β chain are affected | Only β chain is affected |
(b)
Major goals of HGP:
Identify all the genes ($\displaystyle 20,000$-$\displaystyle 25,000$ in human DNA)
Determine the sequence of the three billion base pairs present in human DNA.
Store the information in database.
Improve the tools for data analysis.
Transfer the technologies to other sectors (like industries).
Address the ethical legal and social issues that may arise from this project.
(ii)
Methodologies :
Expressed Sequence Tags (ESTs) , It focuses on identifying all the genes that are expressed as RNAs.
Sequence Annotation , it aims at sequencing the whole set of genome that includes all coding sequences and non coding sequences and then assigning functions to different regions in the sequence.
(iii)
• Yeast artificial chromosomes
• It is used as vector.
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