monohybrid cross

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monohybrid cross

A student draws a monohybrid cross Punnett square on a chalkboard.

Definition

Noun: A monohybrid cross is a genetic cross between two organisms that are both heterozygous for a single specific trait. This means both parents carry two different alleles (gene variants) for the one trait being studied. The purpose of such a cross is to observe the inheritance pattern of that single trait in the offspring.

Usage

A monohybrid cross is a fundamental concept in classical genetics used to analyze the segregation of alleles for one gene. * In a monohybrid cross, the expected phenotypic ratio in the offspring is 3:1 if one allele is dominant over the other. * Mendel established the basic principles of inheritance by performing monohybrid crosses on pea plants. * To predict the outcome of a monohybrid cross, a Punnett square is often used.

Advanced Usage
  • Monohybrid Cross vs. Dihybrid Cross: A monohybrid cross examines one trait (e.g., seed color), while a dihybrid cross examines the inheritance of two different traits simultaneously (e.g., seed color and seed shape).
  • Test Cross Application: A monohybrid cross is the basis for a , where an organism with a dominant phenotype but unknown genotype (could be homozygous or heterozygous) is crossed with a homozygous recessive organism to determine its genotype.
Variants and Related Words
  • Monohybrid (noun/adjective): Refers to an individual that is heterozygous for a single gene or to the cross itself.
  • Dihybrid Cross (noun): A genetic cross examining two traits.
  • Punnett Square (noun): A diagram used to predict the genotypes and phenotypes of offspring from a genetic cross.
Synonyms
  • Single-factor cross
  • Single-trait cross
Related Concepts (Not Phrasal Verbs or Idioms)
  • Mendelian Inheritance: The pattern of inheritance observed in monohybrid crosses follows Mendel's Law of Segregation.
  • Genotype/Phenotype Ratio: The numerical outcome (e.g., 1:2:1 genotypic ratio, 3:1 phenotypic ratio) predicted from a standard monohybrid cross between two heterozygotes.
  • F1 and F2 Generations: In a classic monohybrid experiment, the first filial (F1) generation are all heterozygous and show the dominant phenotype. Crossing two F1 individuals produces the F2 generation, where the 3:1 phenotypic ratio appears.
monohybrid cross

A student draws a monohybrid cross Punnett square on a chalkboard.

Noun
  1. hybridization using a single trait with two alleles (as in Mendel's experiments with garden peas)