target genes/proteins related with the biological phenomenon
under study are provided, hence paving the way for running further
confirmatory (hypothesis-driven) studies [1, 4]. Important profound mechanistic rather than descriptive knowledge in biology
came up thanks to the large use of model organisms. These organisms have special features that make them ideal for research, such as
being smaller, easier to get, maintain and reproduce, and with
shorter growing times, than other less-studied organisms
[5]. Because a practical goal for model organisms has been usually
to develop rather complete molecular tool kits, it has been largely
perceived that a model species could be a synonym of an organism
whose genome is fully sequenced and published. Hence, a narrow
sense definition for model organisms would be those with full
sequenced genomes and good representation in public sequence
databases, while non-model organisms would be those whose genomes have not been sequenced yet and are poorly represented in
nucleotide and protein sequence databases. Hereafter, we will take
this narrow sense definition when referring to non-model
organisms.
An important milestone in molecular biology was the publication in 1995 of the first complete genome of a living organism, the
bacterium Haemophilus influenzae, kicking off modern genomic
era. Since this important achievement, genomic progress has been
extraordinary. Before the end of the 1990s, a total of 42 genomes
had been already sequenced, including the genome of the first
eukaryotic organism (Saccharomyces cerevisiae) in 1996. In 2020
(January 28), according to “Genomes OnLine Database (GOLD)”
[6], there are 336,707 sequencing projects recorded, covering
372,933 different organisms or strains, from which there are only
18,955 organisms (457 are eukaryotes) with their whole genome
completed and published. Additionally, there are whole genome
sequencing projects involving more than 10,000 eukaryotic organisms in an “incomplete” or “permanent draft” status. Despite this
spectacular advance, it is necessary that sequencing efforts are
expanded to a broader number of taxonomic groups and species.
Some non-model organisms, usually more complex than their
widely used counterparts, may contain specific mechanisms or characteristics that made them of high utility for answering questions of
broad biological interest among research community [5] and are
potential candidates to be established as new model organisms
within different (sub)disciplines. For example, if we look specifically
for phylum “Mollusca,” the second largest phylum of invertebrate
animals after Arthropoda with at least 100,000 species, vastly dominated by marine organisms, whole genome sequencing projects
have so far focused on only 51 species (most still are in “permanent
draft” or “incomplete” stage). Many of these mollusk species have
been considered for years as new emerging model organisms in
research fields such as ecotoxicology, biotechnology, biomedical,
developmental, and reproductive biology.
78
Angel P. Diz and Paula Sa ´ nchez-Marı ´n
under study are provided, hence paving the way for running further
confirmatory (hypothesis-driven) studies [1, 4]. Important profound mechanistic rather than descriptive knowledge in biology
came up thanks to the large use of model organisms. These organisms have special features that make them ideal for research, such as
being smaller, easier to get, maintain and reproduce, and with
shorter growing times, than other less-studied organisms
[5]. Because a practical goal for model organisms has been usually
to develop rather complete molecular tool kits, it has been largely
perceived that a model species could be a synonym of an organism
whose genome is fully sequenced and published. Hence, a narrow
sense definition for model organisms would be those with full
sequenced genomes and good representation in public sequence
databases, while non-model organisms would be those whose genomes have not been sequenced yet and are poorly represented in
nucleotide and protein sequence databases. Hereafter, we will take
this narrow sense definition when referring to non-model
organisms.
An important milestone in molecular biology was the publication in 1995 of the first complete genome of a living organism, the
bacterium Haemophilus influenzae, kicking off modern genomic
era. Since this important achievement, genomic progress has been
extraordinary. Before the end of the 1990s, a total of 42 genomes
had been already sequenced, including the genome of the first
eukaryotic organism (Saccharomyces cerevisiae) in 1996. In 2020
(January 28), according to “Genomes OnLine Database (GOLD)”
[6], there are 336,707 sequencing projects recorded, covering
372,933 different organisms or strains, from which there are only
18,955 organisms (457 are eukaryotes) with their whole genome
completed and published. Additionally, there are whole genome
sequencing projects involving more than 10,000 eukaryotic organisms in an “incomplete” or “permanent draft” status. Despite this
spectacular advance, it is necessary that sequencing efforts are
expanded to a broader number of taxonomic groups and species.
Some non-model organisms, usually more complex than their
widely used counterparts, may contain specific mechanisms or characteristics that made them of high utility for answering questions of
broad biological interest among research community [5] and are
potential candidates to be established as new model organisms
within different (sub)disciplines. For example, if we look specifically
for phylum “Mollusca,” the second largest phylum of invertebrate
animals after Arthropoda with at least 100,000 species, vastly dominated by marine organisms, whole genome sequencing projects
have so far focused on only 51 species (most still are in “permanent
draft” or “incomplete” stage). Many of these mollusk species have
been considered for years as new emerging model organisms in
research fields such as ecotoxicology, biotechnology, biomedical,
developmental, and reproductive biology.
78
Angel P. Diz and Paula Sa ´ nchez-Marı ´n