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Trait (biology)

 

 
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Trait (biology)
 
 
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A trait is a distinct variant of a phenotypic
Phenotype

A phenotype is any observable characteristic or trait_ of an organism: such as its morphology , development, biochemical or physiological properties, or behavior....
 character of an organism that may be inherited, environmentally determined or somewhere in between. For example, eye color
Eye color

Eye color is a polygenic trait and is determined by the amount and type of pigments in the eye's Iris . Humans and animals have many phenotypic variations in eye color....
 is a character or abstraction
Abstraction

Abstraction is the process or result of generalization by reducing the information content of a concept or an observable phenomenon, typically in order to retain only information which is relevant for a particular purpose....
 of an attribute, while blue, brown and hazel are traits.

ait may be any single feature or quantifiable measurement of an organism. However, the most useful traits for genetic analysis
Genetic analysis

Genetic analysis can be used generally to describe methods both used in and resulting from the sciences of genetics and molecular biology, or to applied research resulting from this research....
 are present in different forms in different individuals.

A visible trait is the final product of many molecular
Molecular biology

Molecular biology is the study of biology at a molecule level. The field overlaps with other areas of biology and chemistry, particularly genetics and biochemistry....
 and biochemical
Biochemistry

Biochemistry is the study of the chemistry processes in living organisms. It deals with the structure and function of cellular components such as proteins, carbohydrates, lipids, nucleic acids and other biomolecules....
 processes.






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A trait is a distinct variant of a phenotypic
Phenotype

A phenotype is any observable characteristic or trait_ of an organism: such as its morphology , development, biochemical or physiological properties, or behavior....
 character of an organism that may be inherited, environmentally determined or somewhere in between. For example, eye color
Eye color

Eye color is a polygenic trait and is determined by the amount and type of pigments in the eye's Iris . Humans and animals have many phenotypic variations in eye color....
 is a character or abstraction
Abstraction

Abstraction is the process or result of generalization by reducing the information content of a concept or an observable phenomenon, typically in order to retain only information which is relevant for a particular purpose....
 of an attribute, while blue, brown and hazel are traits.

Definition

A trait may be any single feature or quantifiable measurement of an organism. However, the most useful traits for genetic analysis
Genetic analysis

Genetic analysis can be used generally to describe methods both used in and resulting from the sciences of genetics and molecular biology, or to applied research resulting from this research....
 are present in different forms in different individuals.

A visible trait is the final product of many molecular
Molecular biology

Molecular biology is the study of biology at a molecule level. The field overlaps with other areas of biology and chemistry, particularly genetics and biochemistry....
 and biochemical
Biochemistry

Biochemistry is the study of the chemistry processes in living organisms. It deals with the structure and function of cellular components such as proteins, carbohydrates, lipids, nucleic acids and other biomolecules....
 processes. In most cases, information starts with DNA
DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetics instructions used in the development and functioning of all known living organisms and some viruses....
 traveling to RNA
RNA

Ribonucleic acid is a type of molecule that consists of a long chain of nucleotide units. Each nucleotide consists of a nucleobase, a ribose sugar, and a phosphate....
 and finally to protein
Protein

Proteins are organic compounds made of amino acids arranged in a linear chain and joined together by peptide bonds between the carboxyl and amino groups of adjacent amino acid Residue ....
 (ultimately affecting organism structure and function). This is the Central Dogma of molecular biology
Molecular biology

Molecular biology is the study of biology at a molecule level. The field overlaps with other areas of biology and chemistry, particularly genetics and biochemistry....
 as stated by Francis Crick
Francis Crick

Francis Harry Compton Crick Order of Merit Royal Society , Ph.D., was a British molecular biology, physics, and neuroscience, and most noted for being one of the co-discoverers of the structure of the DNA molecule in 1953....
.

This information flow may also be followed through the cell
Cell (biology)

The cell is the structural and functional unit of all known Life organisms. It is the smallest unit of an organism that is classified as living, and is often called the building bricks of life....
 as it travels from the DNA
DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetics instructions used in the development and functioning of all known living organisms and some viruses....
 in the nucleus
Cell nucleus

In cell biology, the nucleus , also sometimes referred to as the "control center", is a membrane-enclosed organelle found in all eukaryote cell ....
, to the Cytoplasm
Cytoplasm

The cytoplasm is the part of a Cell that is enclosed within the plasma membrane. In eukaryote cells the cytoplasm contains organelles, such as mitochondrion, that are filled with liquid kept separate from the rest of the cytoplasm by biological membranes....
, to the Ribosomes and the Endoplasmic Reticulum
Endoplasmic reticulum

The endoplasmic reticulum is a eukaryote organelle that forms an interconnected network of tubules, vesicle , and cisternae within cell . The lacey membranes of the endoplasmic reticulum were first seen by Keith R....
, and finally to the Golgi Apparatus
Golgi apparatus

The Golgi apparatus is an organelle found in most eukaryote Cell . It was identified in 1898 by the Italian physician Camillo Golgi and was named after him....
, which may package the final products for export outside the cell.

Cell products are released into the tissue
Biological tissue

Tissue is a cellular organizational level intermediate between cells and a complete organism. Hence, a tissue is an ensemble of cells, not necessarily identical, but from the same origin, that together carry out a specific function....
, and organ
Organ (anatomy)

In biology, an organ is a biological tissue that performs a specific function or group of functions. Usually there is a main tissue and sporadic tissues....
s of an organism
Organism

In biology, an organism is any life thing . In at least some form, all organisms are capable of response to stimulus , reproduction, growth and developmental biology, and maintenance of homeostasis as a stable whole....
, to finally affect the physiology
Physiology

Physiology is the study of the mechanical, physical, and biochemical functions of living organisms. Physiology has traditionally been divided between plant physiology and animal and all living things physiology but the principles of physiology are universal, no matter what particular organism is being studied....
 in a way that produces a trait.

Genetic origin of traits in diploid organisms

The heritable unit that may influence a trait is called a gene
Gene

A gene is the basic unit of heredity in a living organism. All living things depend on genes. Genes hold the information to build and maintain their cell and pass genetic trait to offspring....
. A gene is a strand of DNA
DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetics instructions used in the development and functioning of all known living organisms and some viruses....
 that is part of a very long and compacted
Histone

In biology, histones are the chief protein components of chromatin. They act as spools around which DNA winds, and they play a role in gene regulation....
 string of DNA
DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetics instructions used in the development and functioning of all known living organisms and some viruses....
 called a chromosome
Chromosome

A chromosome is an organized structure of DNA and protein that is found in Cell . A chromosome is a single piece of DNA that contains many genes, regulatory sequence and other genetic sequence....
. An important reference point along this string is the centromere
Centromere

A centromere is a region of DNA typically found near the middle of a chromosome where two sister chromatids come in contact. It is involved in cell division as the point of mitotic spindle....
; the distance from a gene to the centromere is referred to as the gene's locus
Locus (genetics)

In the fields of genetics and evolutionary computation, a locus is a fixed position on a chromosome such as the position of a genetic marker that may be occupied by one or more genes....
 or map location. A chromosomal region known to control a trait while the responsible gene within not being identified is referred to as a quantitative trait locus
Quantitative trait locus

Inheritance of quantitative traits or polygenic inheritance refers to the inheritance of a phenotype characteristic that varies in degree and can be attributed to the interactions between two or more genes and their environment....
.

The nucleus of a diploid cell contains two of each chromosome, with homologous
Homology (biology)

In evolutionary biology, homology refers to any similarity between characteristics that is due to their common descent. The word homologous derives from the ancient Greek ??????e??, 'to agree'....
 (mostly identical) pairs of chromosomes having the same genes at the same loci
Locus (genetics)

In the fields of genetics and evolutionary computation, a locus is a fixed position on a chromosome such as the position of a genetic marker that may be occupied by one or more genes....
.

Mendelian expression of genes in diploid organisms

A gene is only a DNA code
Genetic code

The genetic code is the set of rules by which information encoded in genetic material is Translation into proteins by living cell s. The code defines a mapping between tri-nucleotide sequences, called codons, and amino acids....
 sequence; the slightly different variations of that sequence are called alleles. Allele
Allele

An allele is one member of a pair or series of different forms of a gene. Usually alleles are coding region, but sometimes the term is used to refer to a junk DNA....
s can be significantly different and produce different product RNA
RNA

Ribonucleic acid is a type of molecule that consists of a long chain of nucleotide units. Each nucleotide consists of a nucleobase, a ribose sugar, and a phosphate....
s.

Combinations of different alleles thus go on to generate different traits through the information flow charted above. For example, if the alleles on homologous chromosome
Chromosome

A chromosome is an organized structure of DNA and protein that is found in Cell . A chromosome is a single piece of DNA that contains many genes, regulatory sequence and other genetic sequence....
s exhibit a "simple dominance" relationship, the trait of the "dominant" allele shows in the phenotype.

Gregor Mendel
Gregor Mendel

Gregor Johann Mendel was an Augustinians priest and scientist, and is often called the father of genetics for his study of the biological inheritance of certain Trait s in pea plants....
 pioneered modern genetics. His most famous analyses were based on clear-cut traits with simple dominance. He determined that the heritable
Inheritance

Inheritance is the practice of passing on property, Title s, debts, and obligations upon the death of an individual. It has long played an important role in human societies....
 units, what he called "gene
Gene

A gene is the basic unit of heredity in a living organism. All living things depend on genes. Genes hold the information to build and maintain their cell and pass genetic trait to offspring....
s", occurred in pairs and could exhibit linkage
Genetic linkage

Genetic linkage occurs when particular genetic Locus or alleles for genes are inherited jointly. Genetic loci on the same chromosome are physically connected and tend to stay together during meiosis, and are thus genetically linked....
. His tool was statistics
Statistics

Statistics is a Mathematics pertaining to the collection, analysis, interpretation or explanation, and presentation of data. It also provides tools for prediction and forecasting based on data....
: long before the molecular model of DNA
DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetics instructions used in the development and functioning of all known living organisms and some viruses....
 was introduced by James D. Watson
James D. Watson

James Dewey Watson is an American molecular biology, best known as one of the co-discoverers of the structure of DNA. Watson, Francis Crick, and Maurice Wilkins were awarded the 1962 Nobel Prize in Physiology or Medicine "for their discoveries concerning the molecular structure of nucleic acids and its significance for information transfer...
 and Francis Crick
Francis Crick

Francis Harry Compton Crick Order of Merit Royal Society , Ph.D., was a British molecular biology, physics, and neuroscience, and most noted for being one of the co-discoverers of the structure of the DNA molecule in 1953....
.

Some examples of Inherited genes include eye color.

Biochemistry of dominance and extensions to expression of traits

The biochemistry
Biochemistry

Biochemistry is the study of the chemistry processes in living organisms. It deals with the structure and function of cellular components such as proteins, carbohydrates, lipids, nucleic acids and other biomolecules....
 of the intermediate proteins determines how they interact in the cell. Therefore, biochemistry predicts
Philosophy of science

The philosophy of science is concerned with the assumptions, foundations, and implications of science. The field is defined by an interest in one of a set of "traditional" problems or an interest in central or foundational concerns in science....
 how combinations of different alleles will produce varying traits.

Extended expression patterns seen in diploid organisms include facets of incomplete dominance, codominance, and multiple alleles.

See also

  • Character displacement
    Character displacement

    Character displacement refers to the phenomenon where differences among similar species whose distributions overlap geographically are accentuated in regions where the species co-occur but are minimized or lost where the species? distributions do not overlap....
  • Skill
    Skill

    A skill is the learned capacity to carry out pre-determined results often with the minimum outlay of time, energy, or both. Skills can often be divided into domain-general and domain-specific skills....