Question

Genetics Question: I am confused on the second part of the question- determining the information for both the donor and recipient. Thank you!

different interrupted mating experiments, you obtain the following data for 2. Ih three the time of entry of the following genes: arg, met, leu, ser, gal, val, and phe. All of these experiments were conducted using Hfr strains (Hfr 1, Hfr 2, and Hfr3) derived from the same original strain of E. coli. Experiment 1 (Hfr 1) Met Val Leu Arg Ser Gal Experiment 2 (Hfr 2) Experiment 3 (Hfr 3) 10 min Gal 25 min Ser 30 min Leu 40 min Val 55 min Met 60 min Phe 5 min Leu 10 min Val 35 min Met 40 min Phe 55 min Gal 85 min Ser 5 min 10 min 25 min 55 min 75 min 80 min a. Determine the order of these genes on the bacterial chromosome and draw a single map showing the position of each of these genes on the bacterial chromosome. Based on the time intervals above, indicate the map distances between each gene, expressed in minutes. Show the origin of transfer and direction of transfer for each Hfr. Also, proyide a brief description of your reasoning. , /, met va/ o met is met is the origin leu of transfer hfr 3 20 and l0 wih apart from htr4 - this Irgic was u5cd to Cons hmct the ar rest of the chromosome hfr2 If the crosses were set up as described in class, what are the genotypes of the donor and recipient cells? b. Donor: Hf y arg sert galt phetmet* val lcu stypS Reci pitnt Far ser gal phe met Nal- leu-StrpR

Answer 1

Strain of bacterial chromosome integrated with F plasmid is called HFr. This strain has ability to function as donar in conjugal mating. This donar transer chromosomal genes to recipient with high efficiency. Strains that lack F plamid is called F^- and behave as recipient. Transfer of single stranded DNA from HFr donar to recipient begins from the origin within F plasmid.

In this inturrpted mating experiment, crosses occur between HFr and F^- . Agitating kitchen blander experiment is used to assessed the recombination of specific genes at different time. These cells were grown on medium containing antibiotic in order to ensure recovery of only recipient cells.

Here donar cell is HFr which is wild type and sensitive to antibiotic to select only recipient after blander experiment

F^- is a recipient cells which are auxotrophic for each marker and its antibiotic resistant and grow on medium containing antibiotic.

In conjugation tra genes are involved that are divided into two type one is involved in mating pair formation and other is whose product are involve in processing of plasmid DNA for transfer. During HFr anf F^- mating segment of F plasmid contain tra region is transferred last after the entire bacterial chromosome is transferred.

At start of cross , all the genes are present on Hfr strains that why represented as HFr positive with antibiotic sensitive strain whereas F^- lack all the genes along with antibiotic resistance. Genotype is determined on the basis of donar and recipient cells and their respective genes.