Southern Blotting: Understanding DNA Fragment Migration in Electrophoresis
Southern blotting: The smaller the DNA fragment….
A. The closer to the origin it will appear
B. The brighter color it produces with ethidium bromide
C. The faster it migrates during separation by electrophoresis
D. The slower it migrates during separation by electrophoresis
Correct Answer: (C) The faster it migrates during separation by electrophoresis
Southern blotting is a widely used molecular biology technique that detects specific DNA sequences within a sample. The process involves DNA digestion with restriction enzymes, gel electrophoresis, membrane transfer, and probe hybridization to identify target DNA fragments.
One of the key steps in Southern blotting is electrophoresis, which separates DNA fragments based on their size.
How DNA Fragment Size Affects Migration in Electrophoresis
During agarose gel electrophoresis, DNA molecules migrate through the gel under an electric field. The movement of DNA is influenced by the following factors:
-
Size of DNA Fragments
- Smaller DNA fragments travel faster and move farther through the gel.
- Larger DNA fragments travel slower and remain closer to the origin (wells).
-
Gel Composition
- Agarose gel concentration affects separation.
- Higher agarose concentration (e.g., 2%) improves the resolution of small DNA fragments.
- Lower agarose concentration (e.g., 0.8%) is better for large DNA fragments.
-
Voltage Applied
- Higher voltage increases migration speed, but excessive voltage can lead to DNA smearing.
Why Option (C) is Correct
Smaller DNA fragments migrate faster through the gel because they experience less resistance from the gel matrix. This makes them move farther from the loading wells compared to larger DNA fragments.
Why Other Options Are Incorrect
-
(A) The closer to the origin it will appear ❌
- Incorrect, because smaller DNA fragments travel farther from the origin, while larger fragments stay closer.
-
(B) The brighter color it produces with ethidium bromide ❌
- Ethidium bromide (EtBr) staining depends on DNA quantity, not size. Larger fragments contain more base pairs, so they bind more EtBr and appear brighter.
-
(D) The slower it migrates during separation by electrophoresis ❌
- Incorrect, because smaller DNA fragments migrate faster, not slower.
Conclusion
In Southern blotting, DNA fragments are separated using electrophoresis, where smaller fragments travel faster through the gel due to reduced resistance. This property is crucial for genetic analysis, disease detection, and forensic studies.
71 Comments
Ujjwal
March 8, 2025✔️👍
Suman bhakar
March 8, 2025👌👌
Aakansha Sharma
August 20, 2025Option C is right
Meena Kumari
March 8, 2025Well
Pooja jat
March 10, 2025Easy one.
Kabeer Narwal
March 22, 2025👍
Arushi
April 9, 2025👍✔️
Khushi Vaishnav
August 17, 2025Faster it migrate during separation by electrophoresis because smaller fragments travel faster
Meenakshi Choudhary
August 18, 2025The faster it migrates during separation by electrophoresis
Neelam Sharma
August 19, 2025The faster it migrates during separation by electrophoresis
Dipti Sharma
August 20, 2025C. The smaller the fragment, the Faster migration during separation .
Anurag Giri
August 20, 2025Option c
The faster it migrates during separation by electrophoresis
Nilofar Khan
August 20, 2025Correct answer is c
Khushi Mehra
August 20, 2025Answer is 3
Smaller the size of DNA fragments , migration rate will be faster towards positive electrode
Dharmpal Swami
August 20, 2025Low molecular weight molecules fast migrate
Mansukh Kapoor
August 20, 2025The correct answer is option 3rd
Smaller fragments move faster in the gel during electrophoresis
Bharti Yadav
August 20, 2025Small DNA fragment will migrate fast in gel electrophoresis.
Priya dhakad
August 20, 2025The faster it migrates during separation by electrophoresis
anjani sharma
August 20, 2025Answer is c as in electrophoresis the lighter weight molecules migrate fast
Surbhi Rajawat
August 20, 2025The correct answer is C. The smaller the DNA fragments they will run faster in the gel
Kavita choudhary
August 20, 2025The Faster it migrat during the separation by electrophoresis
Deepika Sheoran
August 20, 2025Option c is correct answer
The faster migrate during separation by electrophoresis.
Neha
August 21, 2025The smaller the dna fragments migrate faster during separation by electrophoresis
Mohd juber Ali
August 21, 2025Option c
Bcs Northern blotting separate mRna based on size and estimate molecule weight
Low m.w. fast migration
Aman Choudhary
August 21, 2025Option C is correct
Smaller DNA fragment move faster because low molecular weight
Aafreen Khan
August 21, 2025Southern Blotting is an electrophoresis which separates DNA fragments based on their size The small DNA fragments faster it migrates during separation by electrophoresis
Sakshi yadav
August 21, 2025Low molecular weight so particle moves faster during seperation by electrophoresis
Payal Gaur
August 21, 2025Faster migrate small DNA fragments during electrophoresis
Meera Gurjar
August 21, 2025Faster migrate small DNA fragments during electrophoresis
Avni
August 21, 2025The faster it migrates during separation by electrophoresis
Bhawna Choudhary
August 21, 2025The faster it migrate during separation by electrophoresis because smaller DNA fragments move faster because their molecular weight is less
Santosh Saini
August 21, 2025Small fragments Move fast towards the positive charge during gel electrophoresis
Simran Saini
August 21, 2025Option c.
The faster it migrates during separation by electrophoresis.
Komal Sharma
August 22, 2025In Southern blotting, DNA fragments are separated using electrophoresis, where smaller fragments travel faster through the gel due to reduced resistance. This property is crucial for genetic analysis, disease detection, and forensic studies so option C is correct
shruti sharma
August 22, 2025option c
Sakshi Kanwar
August 22, 2025Less molecular weight will migrate faster towards the positive charge ….option C
Priyanka choudhary
August 22, 2025Right answer is option c,
The faster it migrates during separation by electrophoresis
Parul Yadav
August 22, 2025Smaller the fragments faster they moves through the gel because they will experience less resistance from the gel matrix.
karishma
August 22, 2025The smaller the dna fragment, the faster it migrates during separation by electrophoresis
Sakshi
August 22, 2025C is correct
Faster migrate during separation of electrophoresis
Soniya Shekhawat
August 23, 2025Small DNA fragments t move fastest in gel electrophoresis.
Kirti agarwal
August 23, 2025Opt c
Priya khandal
August 23, 2025The faster it migrates during separatiob by electrophoresis
Ankita Pareek
August 23, 2025Smaller fragment move faster in gel because they experience less resistance
Kajal
August 23, 2025The smaller the size of dna fragments tha faster they move looks like size is inversely related to the movement of dna fragment
Bharti Yadav
August 23, 2025The smaller fragment migrate faster during separation by electrophoresis
Yogita
August 24, 2025The faster it migrates during separation by electrophoresis
Sneha Kumawat
August 24, 2025The faster it migrate during separation by electrophoresis
Urmi sisodiya
August 24, 2025Option c is correct because the shorter band of dna moves faster
Shivani
August 24, 2025Option C is correct
Smaller size DNA moves faster during gel electrophoresis
Neeraj Sharma
August 24, 2025Option C is correct the smaller the fragments the faster it travels
Tanvi Panwar
August 24, 2025The smaller the DNA fragment the faster it will run in the electrophoresis.
Surendra Doodi
August 24, 2025The faster it migrates during separation by electrophoresis
Priyanka Verma
August 24, 2025The smaller the DNA fragment the faster it will trave’
Sonam Saini
August 24, 2025Opetion c is Right answer
sakshi khatri
August 24, 2025C is correct answer
Falguni Prakash
August 24, 2025Migrate fast due to less molecular weight
Swati Choudhary
August 24, 2025Smaller fragments move faster in the gel during electrophoresis.
Kajal
August 25, 2025Smaller molecules moves faster in gel electrophoresis
Priyanka Meena
August 26, 2025Small DNA nitrocellulose members pr detect nhi kr pate ye small DNA fast move krte hai fragments by electrophoresis
Muskan Yadav
August 26, 2025The faster it migrates during separation by electrophoresis.
Manisha choudhary
August 27, 2025Small DNA fragments fast move krega, origin( well) s dur hoga
Kanica Sunwalka
August 28, 2025option c
Shriyanshi verma
August 30, 2025Faster it migrate during separation by electrophoresis because smaller fragments travel faster
Asha Gurzzar
August 30, 2025C is correct ,short dna jitna hoga utna fast migrate krega gel me
Alec
August 30, 2025the smaller the Dna fragment the faster it migrates during separation by electrophoresis.
Pratibha Jain
August 30, 2025Correct Answer is option (C)
The smaller the DNA faster it migrates during separation by electrophoresis
Anisha jakhar
August 31, 2025Shorter fragment migrates faster during electrophoresis
Shobha Kanwar
August 31, 2025Correct Answer: (C) The faster it migrates during separation by electrophoresis
Anjali
September 1, 2025(C) The faster it migrates during separation by electrophoresis
Ajay Sharma
September 4, 2025patla aadmi jyada dur tk bhaag skta h