Transformation is the process by which exogenous DNA is introduced into a cell, resulting in an inheritable change or genetic modification. 

 

1-In the case of fungi, the spheroplasts of the budding yeast Saccharomyces cerevisiae were first successfully transformed in 1978 [6].

Abstract:

A stable leu2- yeast strain has been transformed to LEU2+ by using a chimeric ColE1 plasmid carrying the yeast leu2 gene. We have used recently developed hybridization and restriction endonuclease mapping techniques to demonstrate directly the presence of the transforming DNA in the yeast genome and also to determine the arrangement of the sequences that were introduced. These studies show that ColE1 DNA together with the yeast sequences can integrate into the yeast chromosomes. This integration may be additive or substitutive. The bacterial plasmid sequences, once integrated, behave as a simple Mendelian element. In addition, we have determined the genetic linkage relationships for each newly introduced LEU2+ allele with the original leu2- allele. These studies show that the transforming squences integrate not only in the leu2 region but also in several other chromosomal locations

 

2-Several methods to transform intact cells, including the lithium, electroporation, biolistic and glass bead methods, have been developed, and the efficiency of each method has been improved, such as Schizosaccharomyces pombe and Pichia pastoris.

1978

Transformation of yeast by a replicating hybrid plasmid [7]. 

1983

Transformation of intact yeast cells treated with alkali cations [8].

1985

1. A novel method for transformation of intact yeast cells by electroinjection of plasmid DNA [9]. 

2. Intact cell transformation of Saccharomyces cerevisiae by polyethylene glycol [10]. 

1987

Transformation of yeast spheroplasts without cell fusion [11]. 

1988

1.Transformation of yeast by agitation with glass beads [12]. 

2. Mitochondrial transformation in yeast by bombardment with microprojectiles [12]. 

1989

1. Transformation of Saccharomyces cerevisiae by electroporation [13]. 

2. High efficiency transformation of intact yeast cells using single stranded nucleic acids as a carrier [14]. 

1990

Biolistic nuclear transformation of Saccharomyces cerevisiae [15].

1992

1. One-step transformation of yeast in stationary phase [16]. 

2. Improved method for high efficiency transformation of intact yeast cells [17]. 

1995

Studies on the transformation of intact yeast cells by the LiAc/SS-DNA/PEG procedure [18]. 

1998

An improved protocol for the preparation of yeast cells for transformation by electroporation [19]. 

2002

1. Extremely simple, rapid and highly efficient transformation method for the yeast Saccharomyces cerevisiae using glutathione and early log phase cells [20]. 

2. Transformation of yeast by lithium acetate/single-stranded carrier DNA/polyethylene glycol method [21]. 

2007

Frozen competent yeast cells that can be transformed with high efficiency using the LiAc/ SS carrier DNA/PEG method [22].