Differences Between Northern and Southern Hybridization
All are differences in procedure between Northern and Southern hybridization except
(a) DBM membrane is used in northern hybridization
(b) RNA:DNA hybrids are formed in northern hybridization
(c) Initially fragments are separated by electrophoresis in northern hybridization
(d) DNA denaturation is required before blotting in Southern hybridization
The correct answer is (c) Initially fragments are separated by electrophoresis in Northern hybridization.
Introduction to Northern and Southern Hybridization
Northern hybridization and Southern hybridization are two widely used molecular biology techniques for detecting specific nucleic acid sequences. While Northern hybridization detects RNA sequences, Southern hybridization is used for identifying DNA sequences. Both techniques involve the separation of nucleic acids by electrophoresis, transfer to a membrane, and hybridization with a labeled probe.
Understanding the differences between Northern and Southern hybridization is essential for designing accurate experiments and interpreting results correctly. Let’s explore the differences between these two techniques and clarify the correct answer.
Differences Between Northern and Southern Hybridization
1. Target Molecule
- Northern Hybridization: Detects RNA molecules.
- Southern Hybridization: Detects DNA molecules.
2. Type of Hybrid Formed
- Northern Hybridization: Forms an RNA:DNA hybrid (when a DNA probe is used) or RNA:RNA hybrid (if an RNA probe is used).
- Southern Hybridization: Forms a DNA:DNA hybrid using a complementary DNA probe.
3. Membrane Used
- Northern Hybridization: Typically uses nylon or nitrocellulose membranes.
- Southern Hybridization: Often uses nitrocellulose membranes for DNA transfer.
4. Gel Type and Conditions
- Northern Hybridization: Uses denaturing agarose gel (with formaldehyde) to maintain RNA in a single-stranded form.
- Southern Hybridization: Uses agarose gel for size-based separation of DNA fragments.
5. Denaturation Step
- Northern Hybridization: No denaturation is required as RNA is already single-stranded.
- Southern Hybridization: DNA must be denatured into single strands before hybridization.
✅ Correct Answer: (c) Initially fragments are separated by electrophoresis in Northern hybridization
Both Northern and Southern hybridization techniques involve separation of fragments using electrophoresis. Therefore, this is NOT a valid difference between the two techniques, making it the correct answer.
How Northern and Southern Hybridization Work
1. Northern Hybridization
- RNA is extracted from cells or tissues.
- RNA is separated by size using denaturing agarose gel electrophoresis.
- The separated RNA is transferred to a membrane.
- A labeled DNA or RNA probe is introduced to bind to the target RNA sequence, forming an RNA:DNA hybrid.
- Detection is done using radioactive, fluorescent, or chemiluminescent probes.
2. Southern Hybridization
- DNA is extracted and digested with restriction enzymes.
- Fragments are separated by agarose gel electrophoresis.
- The DNA is denatured into single strands.
- The fragments are transferred to a membrane.
- A labeled DNA probe hybridizes with the complementary DNA sequence, forming a DNA:DNA hybrid.
- Detection is done using similar methods as Northern blotting.
Applications of Northern and Southern Hybridization
Applications of Northern Hybridization
- Gene Expression Analysis – Measures the abundance of mRNA transcripts.
- Alternative Splicing Studies – Identifies different transcript isoforms.
- Viral RNA Detection – Detects viral RNA in infected cells.
- Cancer Biomarker Studies – Measures oncogene and tumor suppressor gene expression.
Applications of Southern Hybridization
- DNA Fingerprinting – Identifies genetic variations in forensic and paternity testing.
- Gene Mapping – Determines the location of genes on a chromosome.
- Mutation Detection – Identifies genetic mutations linked to diseases.
- Cloning Verification – Confirms the presence of inserted DNA in cloning experiments.
Advantages of Northern and Southern Hybridization
Advantages of Northern Hybridization
✔ High specificity for detecting RNA transcripts
✔ Quantitative and size-based analysis
✔ High sensitivity using radioactive or fluorescent probes
Advantages of Southern Hybridization
✔ High specificity for DNA sequences
✔ Useful for studying large genomes
✔ Allows identification of mutations and genetic variations
Why Other Options Are Incorrect
(a) DBM Membrane is Used in Northern Hybridization
- DBM (Diazobenzyloxymethyl) membranes are NOT commonly used in Northern blotting; nylon or nitrocellulose membranes are preferred.
(b) RNA:DNA Hybrids Are Formed in Northern Hybridization
- This is correct because Northern blotting typically uses a DNA probe to detect RNA, forming an RNA:DNA hybrid.
(d) DNA Denaturation is Required Before Blotting in Southern Hybridization
- This is true since DNA must be denatured to enable hybridization with a probe.
Importance of Understanding the Differences
Understanding the differences between Northern and Southern hybridization helps researchers choose the correct method based on the target molecule (RNA or DNA) and the type of information required (gene expression vs. genomic mapping).
72 Comments
Asha Gurzzar
August 19, 2025Rna is single stranded or there is no need of seperate fragments or denaturation
Divya rani
August 20, 2025Electrophoresis occurs in both southern and northern blotting before so it is not a difference in between southern and northern blotting techniques.
Aakansha Sharma
August 20, 2025Option C bcz electrophoresis dono blotting tech. me karte h
Ankita Pareek
August 20, 2025Electrophoresis ocurrs in both the techniques so option c is not the valid answer
Santosh Saini
August 20, 2025Electrophoresis is necessary for both tec. ( Southern and northern blotting)
Meenakshi Choudhary
August 20, 2025Option c is right
Initially fragments are separated by electrophoresis in northern hybridization
Aartii
August 20, 2025Electrophoresis
Vijay Marmat
August 20, 2025C ✔️
Nilofar Khan
August 20, 2025Correct answer is c
Diksha Chhipa
August 20, 2025Done
Neelam Sharma
August 20, 2025Electrophoresis for Southern blotting and northern blotting
Dipti Sharma
August 20, 2025(c) Initially fragments are separated by electrophoresis in Northern hybridization.
This step is common in both southern nd northern blotting
anjani sharma
August 20, 2025Electrophoresis is common in southern and northern blotting
Karishma
August 20, 2025electrophoresis is used in both so it is not a valid difference
Khushi Vaishnav
August 20, 2025Initially fragments are separated by electrophoresis in Northern hybridization.
Dharmpal Swami
August 20, 2025Both southern and northern blotting in which initially fragments are separated by gel electrophoresis
Kavita choudhary
August 20, 2025Electrophoresis is common in northern and southern
Mansukh Kapoor
August 20, 2025The correct answer is option 3rd
The statment Initial the fragments are separated by electrophoresis in northern blotting is not correct
Khushi Singh
August 20, 2025Electrophoresis took place in both southern and Northern blotting
Parul Yadav
August 20, 2025Initially fragments are separated by electrophoresis in both Northern and Southern blotting. This is a similarity not a difference between the two.
Priya khandal
August 20, 2025Gel electrophoresis
Priti khandal
August 20, 2025Electrophoresis for Southern and northern
Komal Pareek
August 20, 2025as blotting is post gel technique.
Deepika Sheoran
August 21, 2025Option C is correct
Initially Fragments are separated by gel electrophoresis in Northern blotting hybridization.
Mohd juber Ali
August 21, 2025Option c
Bcz gel electrophoresis for both Northern blotting and southern blotting
Payal Gaur
August 21, 2025Option c electrophoresis is common process in northern and southern blotting technique
Neha
August 21, 2025Initially fragments are separated by electrophoresis in northern blotting this is not the difference in procedure between northern and southern blotting because electrophoresis is used in both techniques to separate fragments on the basis of mol.wt
Sakshi yadav
August 21, 2025Initially fragments are separated by electrophoresis in northern hybridization. common in both DNA and RNA blotting technique
Bharti Yadav
August 21, 2025Electrophoresis is done in both northern and southern blotting
Mitali saini
August 22, 2025Correct Answer: (c) Initially fragments are separated by electrophoresis in Northern hybridization
shruti sharma
August 22, 2025option c
Pooja Sharma
August 22, 2025OPTION (C)✅
Anurag Giri
August 22, 2025Initially fragments are separated by electrophoresis in Northern hybridization.
Aman Choudhary
August 22, 2025Option C is correct
Initially fragments are separated by electrophoresis in Northern hybridization
Aafreen Khan
August 22, 2025Initially fragments are separated by electrophoresis in Northern hybridization bcoz its common in both Northern and Southern Blotting
Niti Tanwar
August 22, 2025Electrophoresis dono technique m krte h (Northern and Southern blotting)
Kirti agarwal
August 22, 2025Initially fragments are separated by electrophoresis in northern hybridization
Simran Saini
August 22, 2025Initially fragments are separated by electrophoresis in northern hybridization.
Avni
August 22, 2025The correct answer is (c) Initially fragments are separated by electrophoresis in Northern hybridization.
Priyanka Choudhary
August 23, 2025Correct answer is option c
Initially fragments are separated by electrophoresis in Northern hybridization
Kajal
August 23, 2025Correct option is c bcz not only in northern blotting but also in southern blotting fragments are separated by gel electrophoresis so this is nt the difference bcz happens in both blotting…….
Priya dhakad
August 23, 2025Option c is correct becoz gel electrophoresis is common process in Northern and Southern blotting.
Akshita Jangid
August 23, 2025Initially fragments are separated by electrophoresis
Soniya Shekhawat
August 23, 2025Initially fragments are separated in gel electrophoresis common in Southern and nothern BLOTTING so it’s not a difference between them.
Ankita Pareek
August 23, 2025Option c is correct
Sakshi Kanwar
August 23, 2025Separation of fragments by electrophoresis are done both in Southern and northern blotting
Option C
Yogita
August 24, 2025Initially fragments are separated in gel electrophoresis is common in southern and northern blotting
Divya Mandhania
August 24, 2025Electrophoresis is common in southern and northern blotting so the option C is correct
Alec
August 24, 2025correct option is c because electrophoresis occurs in both northern and southern blotting.
Arushi Saini
August 24, 2025Electrophoresis is required to seperate fragments in southern as well as in northern blotting
Himanshi
August 24, 2025Initially fragments are separated by electrophoresis in northern hybridization
Sneha Kumawat
August 24, 2025Electrophoresis dono techniques mein ki jaati Hai so the right answer is initially fragments are separated by electrophoresis in Northern hybridization
AKANKSHA RAJPUT
August 24, 2025option C
Shivani
August 24, 2025Initially fragments are separated by electrophoresis in Northern hybridization.
This step is common in both southern and northern blotting so option C is correct .
Anisha Beniwal
August 24, 2025Option C
Neeraj Sharma
August 24, 2025Option C is correct as separation is common in both techniques
Devika
August 24, 2025Initially fragments are separated by electrophoresis in Northern hybridization
Sonam Saini
August 24, 2025Opetion c is Right
Falguni Prakash
August 24, 2025C
Kashish yadav
August 25, 2025Ok sir
Kajal
August 25, 2025Initially fragments are separated by electrophoresis in northern blotting
Bhavana kankhedia
August 26, 2025Initially fragments are separated by electrophoresis in Northern hybridization
Muskan Yadav
August 26, 2025Option (c) is correct – Initially fragments are separated by electrophoresis in Northern hybridization.
Anju
August 26, 2025Ans:c
In both the teq fragments are separated by electrophoresis
Komal Sharma
August 28, 2025Initially fragments are separated by electrophoresis in Northern hybridization
Komal Sharma
August 28, 2025Electrophoresis occurs in both southern and northern blotting before so it is not a difference in between southern and northern blotting techniques.
Shriyanshi verma
August 30, 2025Electrophoresis took place in both southern and Northern blotting
Pratibha Jain
August 30, 2025correct answer is option (c)
Initially fragments are separated by electrophoresis in Northern hybridization.
Anisha jakhar
August 31, 2025Option c
Saniya
August 31, 2025Done
Shobha Kanwar
August 31, 2025Answer is (c) Initially fragments are separated by electrophoresis in Northern hybridization.
Kanica Sunwalka
August 31, 2025fragments aew seperated by electrophoresis in N. hybrdization