A test of a counting model for chiasma interference

Article Abstract:

The use of YEF 392 Saccharomyces cerevisiae strain with two close intervals separated by two conversion hot spots that can identify close double crossovers helps test the Foss counting model for chiasma interference that predicts enrichment of close double crossovers for intervening C(o) events. Analysis of the tetrads reveals that a C(o) event is present at one of the intervening markers in only 6% of the double crossover tetrads while 8.9% of the general population and 11.7% of the tetrads with no crossovers have a C(o) event in one of the intervening markers. This contradicts the counting model prediction, with a statistically significant difference for the comparison of the double crossover and no crossover groups.

Analysis, Saccharomyces, Chromosome replication

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Unicorns revisited

Article Abstract:

Researchers have developed models of direct mutagenesis which some have considered well-established reality. However, their skeptical counterparts have conducted analytical studies of such models. A model defining protein-to-message feedback which leads to the possibility of transcription errors becoming permanent DNA mutations has been refuted. Similarly, a model proposing inherent mutagenic transcription lactose-induced Lac+ revertants has also been challenged. Directed cell mutation theoretical models will always be criticized until a more solid foundation for them is organized.

Models, Mutagenesis

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Hershey

Article Abstract:

Physiologist Alfred Day Hershey's experiment on bacteriophage T2 laid the groundwork for the hypothesis that DNA conveys genetic information. That research used DNA-specific and protein-specific radioactive labels to implicate DNA in heredity. He also conducted studies aimed at describing the physical properties of phage DNA. Hershey developed chromatographic and centrifugal techniques and applied them to the analysis of T2 chromosome structure. His efforts were rewarded with a Nobel prize for Physiology or Medicine in 1969 which he shared with Max Delbruck and Salvadore E. Luria.

Research, Obituary, DNA, Bacteriophages, Hershey, Alfred Day

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