testcross

Thân thiện

A scientist performs a testcross to determine the genotype of a pea plant.

Definition

Noun: A testcross is a specific type of genetic cross performed between an individual with a dominant phenotype but unknown genotype (it could be either homozygous dominant or heterozygous) and an individual that is homozygous recessive for the trait in question. The purpose is to determine the unknown genotype of the first individual by analyzing the phenotypes of the offspring.

Usage

A testcross is a fundamental tool in Mendelian genetics used to reveal the genetic makeup (genotype) of an organism. - It is used when an organism shows a dominant trait, but its exact genetic composition is unknown. - The homozygous recessive individual used in the cross is often called the "tester" because it reveals the test subject's genotype.

Examples

Advanced Usage

• Testcross Data Analysis: The interpretation of offspring ratios is critical. If all offspring show the dominant trait, the unknown parent is homozygous dominant. If the offspring show a 1:1 ratio of dominant to recessive traits, the unknown parent is heterozygous.
• Linkage Mapping: Testcrosses are essential in creating genetic linkage maps. They are used to calculate recombination frequencies between genes by crossing a heterozygous individual (for the genes of interest) with a homozygous recessive tester.

Variants and Related Words

• Testcross (verb): The act of performing this genetic cross. (e.g., )
• Backcross: A more general term for crossing a hybrid with one of its parents or an organism genetically similar to a parent. A testcross is a specific type of backcross where the parent is homozygous recessive.
• Tester Strain: The homozygous recessive strain or individual used in the testcross.

Synonyms

• Genetic test cross
• Backcross (in the specific context of using a homozygous recessive parent)

Related Concepts (Not Phrasal Verbs or Idioms)

• Genotype Determination: The primary goal of a testcross.
• Homozygous Recessive: The necessary genotype of the "tester" organism in a standard testcross.
• Phenotypic Ratio: The pattern observed in the offspring (e.g., all dominant, or 1:1 dominant:recessive) that provides the answer.

Học thuật

Noun

1. a cross between an organism whose genotype for a certain trait is unknown and an organism that is homozygous recessive for that trait so the unknown genotype can be determined from that of the offspring

Từ đồng nghĩa

• test-cross