What Is The Genetic Makeup Of An Organism Called?

Office of the genetic makeup of a jail cell which determines ane of its characteristics

The genotype of an organism is its complete set of genetic material.^[1] Genotype tin can also be used to refer to the alleles or variants an individual carries in a particular factor or genetic location.^[2] The number of alleles an individual can have in a specific cistron depends on the number of copies of each chromosome found in that species, also referred to as ploidy. In diploid species like humans, two full sets of chromosomes are present, meaning each private has two alleles for any given gene. If both alleles are the same, the genotype is referred to as homozygous. If the alleles are different, the genotype is referred to as heterozygous.

Genotype contributes to phenotype, the observable traits and characteristics in an individual or organism.^[3] The caste to which genotype affects phenotype depends on the trait. For instance, the petal color in a pea plant is exclusively determined by genotype. The petals can be purple or white depending on the alleles present in the pea found.^[4] All the same, other traits are just partially influenced past genotype. These traits are often called complex traits because they are influenced by additional factors, such every bit ecology and epigenetic factors. Not all individuals with the same genotype look or act the aforementioned way because appearance and behavior are modified by environmental and growing conditions. Too, non all organisms that look akin necessarily have the same genotype.

The term genotype was coined past the Danish botanist Wilhelm Johannsen in 1903.^[5]

Phenotype [edit]

Whatsoever given gene will usually cause an appreciable change in an organism, known as the phenotype. The terms genotype and phenotype are distinct for at least ii reasons:

• To distinguish the source of an observer's knowledge (1 can know most genotype by observing DNA; one tin can know about phenotype by observing outward appearance of an organism).
• Genotype and phenotype are non always directly correlated. Some genes only express a given phenotype in sure environmental weather. Conversely, some phenotypes could exist the consequence of multiple genotypes. The genotype is unremarkably mixed up with the phenotype which describes the end result of both the genetic and the environmental factors giving the observed expression (east.g. bluish optics, hair color, or various hereditary diseases).

A uncomplicated example to illustrate genotype every bit distinct from phenotype is the flower color in pea plants (see Gregor Mendel). There are three available genotypes, PP (homozygous dominant ), Pp (heterozygous), and pp (homozygous recessive). All three have different genotypes but the first two take the aforementioned phenotype (purple) as distinct from the 3rd (white).

A more than technical example to illustrate genotype is the single-nucleotide polymorphism or SNP. A SNP occurs when corresponding sequences of DNA from different individuals differ at 1 Dna base of operations, for example where the sequence AAGCCTA changes to AAGCTTA.^[6] This contains two alleles : C and T. SNPs typically have three genotypes, denoted generically AA Aa and aa. In the example above, the three genotypes would be CC, CT and TT. Other types of genetic marker, such as microsatellites, can have more than than 2 alleles, and thus many different genotypes.

Penetrance is the proportion of individuals showing a specified genotype in their phenotype under a given fix of ecology atmospheric condition.^[7]

Mendelian inheritance [edit]

Hither the relation between genotype and phenotype is illustrated, using a Punnett square, for the character of petal colour in a pea plant. The messages B and b stand for alleles for colour and the pictures show the resultant flowers. The diagram shows the cross betwixt two heterozygous parents where B represents the dominant allele (purple) and b represents the recessive allele (white).

Traits that are adamant exclusively by genotype are typically inherited in a Mendelian pattern. These laws of inheritance were described extensively past Gregor Mendel, who performed experiments with pea plants to determine how traits were passed on from generation to generation.^[8] He studied phenotypes that were hands observed, such as found peak, petal color, or seed shape.^[eight] He was able to observe that if he crossed 2 true-breeding plants with distinct phenotypes, all the offspring would take the same phenotype. For example, when he crossed a tall found with a short found, all the resulting plants would be tall. Still, when he self-fertilized the plants that resulted, about 1/four of the second generation would be short. He concluded that some traits were dominant, such as alpine height, and others were recessive, like brusk acme. Though Mendel was not aware at the fourth dimension, each phenotype he studied was controlled by a single gene with two alleles. In the case of institute height, 1 allele caused the plants to be tall, and the other acquired plants to exist short. When the tall allele was present, the plant would exist tall, even if the plant was heterozygous. In order for the plant to be short, it had to exist homozygous for the recessive allele.^{[8] [nine]}

1 style this can be illustrated is using a Punnett foursquare. In a Punnett square, the genotypes of the parents are placed on the exterior. An uppercase letter is typically used to represent the dominant allele, and a lowercase letter is used to represent the recessive allele. The possible genotypes of the offspring tin then be adamant past combining the parent genotypes.^[10] In the example on the right, both parents are heterozygous, with a genotype of Bb. The offspring can inherit a ascendant allele from each parent, making them homozygous with a genotype of BB. The offspring can inherit a dominant allele from ane parent and a recessive allele from the other parent, making them heterozygous with a genotype of Bb. Finally, the offspring could inherit a recessive allele from each parent, making them homozygous with a genotype of bb. Plants with the BB and Bb genotypes will wait the same, since the B allele is dominant. The institute with the bb genotype will have the recessive trait.

These inheritance patterns can also exist practical to hereditary diseases or conditions in humans or animals.^{[11] [12] [13]} Some conditions are inherited in an autosomal dominant pattern, meaning individuals with the condition typically have an afflicted parent also. A classic pedigree for an autosomal dominant condition shows affected individuals in every generation.^{[11] [12] [13]}

An instance of a pedigree for an autosomal dominant condition

Other conditions are inherited in an autosomal recessive pattern, where afflicted individuals do not typically have an afflicted parent. Since each parent must take a copy of the recessive allele in order to have an affected offspring, the parents are referred to equally carriers of the condition.^{[11] [12] [13]} In autosomal conditions, the sexual practice of the offspring does not play a office in their risk of being affected. In sexual practice-linked weather condition, the sex of the offspring affects their chances of having the condition. In humans, females inherit 2 X chromosomes, one from each parent, while males inherit an X chromosome from their mother and a Y chromosome from their father. Ten-linked ascendant atmospheric condition can be distinguished from autosomal dominant conditions in pedigrees by the lack of transmission from fathers to sons, since affected fathers but laissez passer their X chromosome to their daughters.^{[xiii] [14] [fifteen]} In X-linked recessive weather, males are typically affected more than usually because they are hemizygous, with only one X chromosome. In females, the presence of a second X chromosome will prevent the status from actualization. Females are therefore carriers of the condition and can pass the trait on to their sons.^{[13] [14] [fifteen]}

An case of a pedigree for an autosomal recessive condition

Mendelian patterns of inheritance tin be complicated by additional factors. Some diseases testify incomplete penetrance, meaning not all individuals with the illness-causing allele develop signs or symptoms of the disease.^{[13] [16] [17]} Penetrance tin also be age-dependent, meaning signs or symptoms of affliction are not visible until later in life. For example, Huntington disease is an autosomal dominant condition, but up to 25% of individuals with the affected genotype will not develop symptoms until after historic period fifty.^[18] Another gene that tin complicate Mendelian inheritance patterns is variable expressivity, in which individuals with the aforementioned genotype show different signs or symptoms of illness.^{[thirteen] [16] [17]} For case, individuals with polydactyly can have a variable number of extra digits.^{[16] [17]}

Non-Mendelian inheritance [edit]

Many traits are not inherited in a Mendelian fashion, but have more complex patterns of inheritance.

Incomplete dominance [edit]

For some traits, neither allele is completely dominant. Heterozygotes often have an appearance somewhere in betwixt those of homozygotes.^{[19] [20]} For case, a cross between truthful-breeding red and white Mirabilis jalapa results in pinkish flowers.^[20]

Codominance [edit]

Codominance refers to traits in which both alleles are expressed in the offspring in approximately equal amounts.^[21] A classic example is the ABO blood grouping organization in humans, where both the A and B alleles are expressed when they are present. Individuals with the AB genotype have both A and B proteins expressed on their red blood cells.^{[21] [22]}

Epistasis [edit]

Epistasis is when the phenotype of one gene is affected by one or more other genes.^[23] This is often through some sort of masking effect of one factor on the other.^[24] For instance, the "A" gene codes for pilus color, a dominant "A" allele codes for brown hair, and a recessive "a" allele codes for blonde hair, but a separate "B" cistron controls pilus growth, and a recessive "b" allele causes alopecia. If the individual has the BB or Bb genotype, then they produce hair and the hair color phenotype can be observed, merely if the individual has a bb genotype, and so the person is baldheaded which masks the A factor entirely.

Polygenic traits [edit]

A polygenic trait is 1 whose phenotype is dependent on the additive furnishings of multiple genes. The contributions of each of these genes are typically small and add together up to a final phenotype with a large amount of variation. A well studied instance of this is the number of sensory bristles on a wing.^[25] These types of additive effects is also the explanation for the amount of variation in human center colour.

Genotyping [edit]

Genotyping refers to the method used to determine an private's genotype. There are a multifariousness of techniques that tin exist used to assess genotype. The genotyping method typically depends on what data is beingness sought. Many techniques initially require distension of the Deoxyribonucleic acid sample, which is commonly done using PCR.

Some techniques are designed to investigate specific SNPs or alleles in a particular gene or gear up of genes, such as whether an individual is a carrier for a particular status. This tin be washed via a variety of techniques, including allele specific oligonucleotide (ASO) probes or DNA sequencing.^{[26] [27]} Tools such as multiplex ligation-dependent probe amplification can also be used to wait for duplications or deletions of genes or gene sections.^[27] Other techniques are meant to assess a big number of SNPs across the genome, such every bit SNP arrays.^{[26] [27]} This blazon of technology is normally used for genome-broad association studies.

Large-scale techniques to appraise the entire genome are also bachelor. This includes karyotyping to determine the number of chromosomes an individual has and chromosomal microarrays to assess for large duplications or deletions in the chromosome.^{[26] [27]} More detailed information can exist determined using exome sequencing, which provides the specific sequence of all DNA in the coding region of the genome, or whole genome sequencing, which sequences the entire genome including non-coding regions.^{[26] [27]}

See also [edit]

• Endophenotype
• Genotype–phenotype distinction
• Nucleic acrid sequence
• Phenotype
• Sequence (biology)

References [edit]

1. ^ "What is genotype? What is phenotype? – pgEd". pged.org . Retrieved 2020-06-22 .
2. ^ "Genotype". Genome.gov . Retrieved 2021-11-09 .
3. ^ Pierce, Benjamin (2020). Genetics A Conceptual Approach. NY, New York: Macmillian. ISBN978-1-319-29714-5.
4. ^ Alberts B, Bray D, Hopkin Chiliad, Johnson A, Lewis J, Raff M, Roberts Thousand, Walter P (2014). Essential Cell Biology (4th ed.). New York, NY: Garland Science. p. 659. ISBN978-0-8153-4454-four.
5. ^ Johannsen West (1903). "Om arvelighed i samfund og i rene linier". Oversigt Birdy over Det Kongelige Danske Videnskabernes Selskabs Forhandlingerm (in Danish). 3: 247–seventy. German language ed. "Erblichkeit in Populationen und in reinen Linien" (in German language). Jena: Gustav Fischer. 1903. Archived from the original on 2009-05-30. Retrieved 2017-07-19 . . Likewise see his monograph Johannsen West (1905). Arvelighedslærens elementer horse [The Elements of Heredity] (in Danish). Copenhagen. which was rewritten, enlarged and translated into German as Johannsen West (1905). Elemente der exakten Erblichkeitslehre (in German). Jena: Gustav Fischer. Archived from the original on 2009-05-30. Retrieved 2017-07-19 .
6. ^ Vallente, R. U., PhD. (2020). Single Nucleotide Polymorphism. Salem Printing Encyclopedia of Science.
7. ^ Allaby, Michael, ed. (2009). A dictionary of zoology (tertiary ed.). Oxford: Oxford University Printing. ISBN9780199233410. OCLC 260204631.
8. ^ ^{a b c} "Gregor Mendel and the Principles of Inheritance | Larn Science at Scitable". world wide web.nature.com . Retrieved 2021-xi-15 .
9. ^ "12.1 Mendel's Experiments and the Laws of Probability - Biology | OpenStax". openstax.org . Retrieved 2021-11-15 .
10. ^ "3.6: Punnett Squares". Biology LibreTexts. 2016-09-21. Retrieved 2021-xi-15 .
11. ^ ^{a b c} Brotherhood, Genetic; Wellness, Commune of Columbia Department of (2010-02-17). Classic Mendelian Genetics (Patterns of Inheritance). Genetic Alliance.
12. ^ ^{a b c} "Mendelian Inheritance". Genome.gov . Retrieved 2021-11-fifteen .
13. ^ ^{a b c d e f yard} Strachan, T. (2018). Human molecular genetics. Andrew P. Read (fifth ed.). New York: Garland Science. ISBN978-0-429-82747-1. OCLC 1083018958.
14. ^ ^{a b} Alliance, Genetic; Wellness, District of Columbia Department of (2010-02-17). Classic Mendelian Genetics (Patterns of Inheritance). Genetic Alliance.
15. ^ ^{a b} "iv.4.1: Inheritance patterns for X-linked and Y-linked genes". Biology LibreTexts. 2020-06-24. Retrieved 2021-11-15 .
16. ^ ^{a b c} "14.2: Penetrance and Expressivity". Biology LibreTexts. 2021-01-13. Retrieved 2021-11-19 .
17. ^ ^{a b c} "Phenotype Variability: Penetrance and Expressivity | Learn Scientific discipline at Scitable". www.nature.com . Retrieved 2021-11-19 .
18. ^ Caron, Nicholas S.; Wright, Galen EB; Hayden, Michael R. (1993), Adam, Margaret P.; Ardinger, Holly H.; Pagon, Roberta A.; Wallace, Stephanie Eastward. (eds.), "Huntington Disease", GeneReviews®, Seattle (WA): University of Washington, Seattle, PMID 20301482, retrieved 2021-eleven-19
19. ^ "Genetic Say-so: Genotype-Phenotype Relationships | Learn Science at Scitable". www.nature.com . Retrieved 2021-11-15 .
20. ^ ^{a b} Frizzell, Yard.A. (2013), "Incomplete Dominance", Brenner's Encyclopedia of Genetics, Elsevier, pp. 58–60, doi:ten.1016/b978-0-12-374984-0.00784-one, ISBN978-0-08-096156-9 , retrieved 2021-11-xv
21. ^ ^{a b} Xia, X. (2013), "Codominance", Brenner'south Encyclopedia of Genetics, Elsevier, pp. 63–64, doi:10.1016/b978-0-12-374984-0.00278-three, ISBN978-0-08-096156-9 , retrieved 2021-11-15
22. ^ "Genetic Dominance: Genotype-Phenotype Relationships | Learn Science at Scitable". world wide web.nature.com . Retrieved 2021-11-15 .
23. ^ Gros, Pierre-Alexis; Nagard, Hervé Le; Tenaillon, Olivier (2009-05-01). "The Evolution of Epistasis and Its Links With Genetic Robustness, Complication and Drift in a Phenotypic Model of Adaptation". Genetics. 182 (ane): 277–293. doi:10.1534/genetics.108.099127. ISSN 0016-6731. PMC2674823. PMID 19279327.
24. ^ Rieger, Rigomar. (1976). Glossary of genetics and cytogenetics : classical and molecular. Michaelis, Arnd,, Green, Melvin Chiliad. (quaternary completely rev. ed.). Berlin: Springer-Verlag. ISBN0-387-07668-9. OCLC 2202589.
25. ^ Mackay, T. F. (Dec 1995). "The genetic basis of quantitative variation: numbers of sensory bristles of Drosophila melanogaster equally a model system". Trends in Genetics. 11 (12): 464–470. doi:10.1016/s0168-9525(00)89154-four. ISSN 0168-9525. PMID 8533161.
26. ^ ^{a b c d} Jain, Kewal M. (2015), Jain, Kewal G. (ed.), "Molecular Diagnostics in Personalized Medicine", Textbook of Personalized Medicine, New York, NY: Springer, pp. 35–89, doi:ten.1007/978-1-4939-2553-7_2, ISBN978-1-4939-2553-7 , retrieved 2021-11-19
27. ^ ^{a b c d east} Wallace, Stephanie Due east.; Bean, Lora JH (2020-06-eighteen). Educational Materials — Genetic Testing: Current Approaches. University of Washington, Seattle.

External links [edit]

Wikimedia Commons has media related to Genotypes.

• Genetic nomenclature

Source: https://en.wikipedia.org/wiki/Genotype

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