Recombination in bacteriophage T4.

摘要: Publisher Summary This chapter discusses that study on genetic recombination in phage T4 shows the participating DNA molecules are broken and rejoined during process. It appears, likely, breakage rejoining may account for all recombination, as extent of breakage, measured by physical methods, is rather good agreement with exchange, methods. In crosses, there average 20 exchanges per genome these apparently clustered to some extent. Isotope transfer experiments indicate a bimodal distribution parental DNA; progeny particles, which receive any label, 5–10%, or less than 1% chromosomal equivalent. The explores joining fragments occurs several steps, mediated specific enzymes. intermediate structures, complementary sections different origin held together hydrogen bonds involved base pairing. Subsequently, become covalently linked. Physically hybrid regions base-paired structures be genetically heterozygous. They homozygous only after replicated repaired. Average frequencies unit length higher crosses most other systems. One map corresponds 100–200 nucleotide pairs, both according measurements. However, frequency not equal over entire genome.