''Kluyveromyces lactis'' is a ''

Kluyveromyces ''Kluyveromyces'' is a genus of ascomycetous yeasts in the family Saccharomycetaceae. Some of the species, such as '' K. marxianus'', are the teleomorphs of '' Candida species''. The genus name of ''Kluyveromyces'' is in honour of Albert Jan Klu ...

yeast Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are estimated to constitut ...

commonly used for genetic studies and industrial applications. Its name comes from the ability to assimilate lactose and convert it into

lactic acid Lactic acid is an organic acid. It has a molecular formula . It is white in the solid state and it is miscible with water. When in the dissolved state, it forms a colorless solution. Production includes both artificial synthesis as well as natu ...

. ''Kluyveromyces lactis'' (formerly ''Saccharomyces lactis'') is a yeast which has the ability to assimilate lactose and convert it into lactic acid. ''K. lactis'' and other organisms i.e., ''Aspergillus niger'' var awamori and ''Escherichia coli'' K-12 are grown in fermenters to produce

chymosin Chymosin or rennin is a protease found in rennet. It is an aspartic endopeptidase belonging to MEROPS A1 family. It is produced by newborn ruminant animals in the lining of the abomasum to curdle the milk they ingest, allowing a longer reside ...

( rennet) on a commercial scale; this rennet, which replaces the conventional form obtained from slaughtered animals, is now widely used in cheese production. Yeasts and fungi are ideal organisms for comparative genomic studies in eukaryotes because of their small and compact genomes and because they include a number of species such as ''Neurospora crassa'', ''Saccharomyces cerevisiae'' and ''Schizosaccharomyces pombe'', that have been, and continue to be, used extensively in genetic studies. However, the divergence between these three species is ancient (estimated to be at least 300 million years old) and the organization of their genomes is quite different. The diversity of the hemiascomycetes, a group of ascomycetes that contains most of the known yeast species, was first explored in 2000. Complete sequencing and comparison of four hemiascomycetous yeasts has been undertaken for ''Candida glabrata'', ''Kluyveromyces lactis'', ''Debaryomyces hansenii'', and ''Yarrowia lipolytica''. They were selected on the basis of their phylogenetic positions and their specific interest as human pathogens, or as industrially or environmentally important yeasts. This work, which represents the first multispecies exploration of genome evolution across an entire eukaryotic phylum, reveals the variety of events and mechanisms that have taken place, and should allow useful comparisons with other phyla of multicellular organisms when more genome sequences are determined. ''K. lactis'' is a heterothallic species with a predominantly haplontic cycle, in contrast to ''S. cerevisia''e in which the predominantly diplobiontic cycle is pseudo-heterothallic due to mating-type switching.

Genomics analysis

In the 1990s, few genes were known and analysed by scientists until the first genomic analysis was performed by a team of the Pasteur Institute of Paris. The

genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ge ...

''Kluyveromyces lactis'' was explored by sequencing 588 short tags from two random genomic libraries (random sequenced tags, or RSTs). 296 ''K. lactis'' genes were identified of which 292 were new. The complete genome of ''K. lactis'' was sequenced in 2004. This species has roughly 5,300 genes spread out over six nuclear chromosomes and its mitochondrial genome. The six chromosomes are labeled A-F.

References

{{Taxonbar, from=Q6421540 Saccharomycetaceae Fungi in cultivation