Monohybrid cross: Difference between revisions
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In [[Gene|genetics]], a '''monohybrid cross''' is a cross between individuals who are identically [[heterozygous]] at one locus, for example, Bb x Bb (see the Punnett square below). | |||
Monohybrid inheritance is the inheritance of a single characteristic. The different forms of the characteristic are usually controlled by different alleles of the same gene. For example, a monohybrid cross between two pure-breeding plants (homozygous for their respective traits), one with yellow seeds (the dominant trait) and one with green seeds (the recessive trait), would be expected to produce an F1 (first) generation with only yellow seeds because the allele for yellow seeds is dominant to that of green. A monohybrid cross compares only one trait. | Monohybrid inheritance is the inheritance of a single characteristic. The different forms of the characteristic are usually controlled by different alleles of the same gene. For example, a monohybrid cross between two pure-breeding plants (homozygous for their respective traits), one with yellow seeds (the dominant trait) and one with green seeds (the [[recessive]] trait), would be expected to produce an F1 (first) generation with only yellow seeds because the allele for yellow seeds is dominant to that of green. A monohybrid cross compares only one trait. | ||
== Monohybrid Cross in Punnett Square== | == Monohybrid Cross in Punnett Square== | ||
Generally, [[dominant]] characteristics are represented with a capital letter, e.g. '''B''', and [[recessive]] characteristics are represented by a lower case letter, e.g. '''b'''. | Generally, [[dominant]] characteristics are represented with a capital letter, e.g. '''B''', and [[recessive]] characteristics are represented by a lower case letter, e.g. '''b'''. | ||
{| width="30%" border="1" cellpadding="3" cellspacing="0" align="center" | |||
|- | |||
|width=33% | | |||
|width=33% align="center"|'''B''' | |||
|width=33% align="center"|'''b''' | |||
|- | |||
|width=33% align="center"|'''B''' | |||
|width=33% align="center" bgcolor=#FFDB58|BB | |||
|width=33% align="center" bgcolor=#FFDB58|Bb | |||
|- | |||
|width=33% align="center"|'''b''' | |||
|width=33% align="center" bgcolor=#FFDB58|Bb | |||
|width=33% align="center" bgcolor="lightgreen"|bb | |||
|} | |||
For a monohybrid cross, the parental genotypes are [[homozygous]], and their progeny, now the [[F1 hybrid|F1]] generation, are all [[heterozygous]]. The above table, a [[Punnett square]], illustrates the results of a cross between two F1 [[heterozygous]] individuals. The result is a 1:2:1 genotypic ratio, and a 3:1 phenotypic ratio. | For a monohybrid cross, the parental genotypes are [[homozygous]], and their progeny, now the [[F1 hybrid|F1]] generation, are all [[heterozygous]]. The above table, a [[Punnett square]], illustrates the results of a cross between two F1 [[heterozygous]] individuals. The result is a 1:2:1 genotypic ratio, and a 3:1 phenotypic ratio. | ||
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Generally, the monohybrid cross is used to determine the F2 generation from a pair of homozygous grandparents (one grandparent dominant, the other recessive) which results in a F1 generation that are all heterozygous. The pairing of these offspring results in a monohybrid cross and results in the F2 generation, with a 75% chance for the dominant phenotype and a 25% chance for the recessive phenotype. | Generally, the monohybrid cross is used to determine the F2 generation from a pair of homozygous grandparents (one grandparent dominant, the other recessive) which results in a F1 generation that are all heterozygous. The pairing of these offspring results in a monohybrid cross and results in the F2 generation, with a 75% chance for the dominant phenotype and a 25% chance for the recessive phenotype. | ||
== | ==Attribution== | ||
{{WPAttribution}} | |||
==Footnotes== | |||
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[[Category:Suggestion Bot Tag]] | |||
Latest revision as of 10:06, 25 September 2024
In genetics, a monohybrid cross is a cross between individuals who are identically heterozygous at one locus, for example, Bb x Bb (see the Punnett square below).
Monohybrid inheritance is the inheritance of a single characteristic. The different forms of the characteristic are usually controlled by different alleles of the same gene. For example, a monohybrid cross between two pure-breeding plants (homozygous for their respective traits), one with yellow seeds (the dominant trait) and one with green seeds (the recessive trait), would be expected to produce an F1 (first) generation with only yellow seeds because the allele for yellow seeds is dominant to that of green. A monohybrid cross compares only one trait.
Monohybrid Cross in Punnett Square
Generally, dominant characteristics are represented with a capital letter, e.g. B, and recessive characteristics are represented by a lower case letter, e.g. b.
| B | b | |
| B | BB | Bb |
| b | Bb | bb |
For a monohybrid cross, the parental genotypes are homozygous, and their progeny, now the F1 generation, are all heterozygous. The above table, a Punnett square, illustrates the results of a cross between two F1 heterozygous individuals. The result is a 1:2:1 genotypic ratio, and a 3:1 phenotypic ratio.
Usage of Monohybrid Cross
Generally, the monohybrid cross is used to determine the F2 generation from a pair of homozygous grandparents (one grandparent dominant, the other recessive) which results in a F1 generation that are all heterozygous. The pairing of these offspring results in a monohybrid cross and results in the F2 generation, with a 75% chance for the dominant phenotype and a 25% chance for the recessive phenotype.
Attribution
- Some content on this page may previously have appeared on Wikipedia.
Footnotes