cloning protocol, Biology

Assignment Help:
Sally Subcloner wants to clone a fragment into pUC19 (Map above – From New England Biolabs). Her fragment was a protein coding gene of 2.7 kb, and had XhoI sites on either end (and no other XhoI sites any where else) and she agarose gel purified this fragment to ensure it was pure. As no XhoI sites existed in the pUC19 plasmid, she decided to clone it into the Sal1 site, as Sal1 and Xho1 have identical overhangs of 5’-TCGA-3’ and therefore she believes that they can be ligated to one another.

As she was using blue/white screening she did not bother with Alkaline Phosphate treatment and ligated the XhoI fragment directly with SalI digested pUC19. After transformation into E. coli (strain AG1 using heat shock treatment) she plated cells onto media with Ampicillin selection (100 mg/mL) and obtained over 300 ampicillin resistant colonies. However none of these were white colonies, only blue, which she interpreted as obtaining no plasmids with the fragment she was aiming to subclone.

(a) Was her cloning approach valid and what was the reason that she could not get white colonies from this protocol? If she modifies the protocol to address this question, what additional advice can you give Sally Subcloner to increase her chances of obtaining white colonies. (10 Marks)

(b) After taking this advice and obtaining white colonies, she purified the plasmid from five different white colonies digested them with Xho1 and ran them on a gel (see below). However there were three bands in each lane, with the major band running at approximately 4.5 kb, instead of 2.7 kb that she expected her XhoI fragment to be. Could these plasmids still be the right recombinant and what simple experiment could she perform to determine this? (Hint what control should have been included in the gel?) (10 Marks)

Related Discussions:- cloning protocol

Extravascular compression, Most of the coronary blood flow to the left vent...

Most of the coronary blood flow to the left ventricular myocardium occurs during diastole. Thus the contracting heart obstructs its own blood supply. The systolic compressive force

Role of fat or lipids in metabolism, ROLE OF FAT OR LIPIDS - Made up...

ROLE OF FAT OR LIPIDS - Made up of fatty acids & glycerol. Linked by ester bond. Maximum quantity of energy is librated. Helpful in temperature regulation. As stored f

Determine push-ups test for check the body strength, Determine Push-ups Tes...

Determine Push-ups Test for check the Body Strength? Push-ups is another test done to measure muscular strength, as well as, endurance and done on a parallel bar. The subject

Determine the food sources of iodine, Determine the Food Sources of Iodine?...

Determine the Food Sources of Iodine? Please note that unlike other minerals studied so far, like selenium, the iodine concentration in foods is highly variable and also depend

Integrated approach plus mastering, I recently rented Physiology, An Integr...

I recently rented Physiology, An Integrated Approach and I was looking online because I have to also get the A&P access code and realize I could have rented it too with my book. Is

Things to do during a cyclone, (a)   For any individual :               ...

(a)   For any individual :                  ·          We should check house, doors and windows and have them repaired whenever necessary.                  ·          We shou

Explain precautions for preparation of general purpose media, Explain Preca...

Explain Precautions for preparation of general purpose media 1. Dissolve ingredients one by one in distilled water. 2. Check and set the medium to appropriate pH. 3. Auto

What do you mean by hemodialysis, Q. What do you mean by hemodialysis? ...

Q. What do you mean by hemodialysis? Hemodialysis is the artificial blood filtration made by specific machines in alternative of the kidneys. Hemodialysis may be necessary in p

Define gonads and reproductive system, Define Gonads and Reproductive Syste...

Define Gonads and Reproductive System? With aging, there is decrease in pituitary hormone secretion causing decrease in gonadal hormone production, which causes number of chang

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd