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Dihybrid Inheritance

 
11.2 Dihybrid Inheritance
 
Definition of Dihybrid Cross
Involves inheritance of two characteristics, each characteristic is controlled by a different gene located at a different locus.
 
Dihybrid Inheritance of Characteristics, Seed Shape and Colour Seed of Pea Plant 
  • The diagram below shows a schematic diagram of a dihybrid inheritance between two purebreed parents to study the characteristics of pea, namely seed colour and seed shape.
  • The two purebreed parents either have a pair of homozygous dominant alleles or a pair of homozygous recessive alleles.
  • Fertilisation between the two purebreed parents produce offsprings in F1 generation with the dominant traits of round and yellow seeds.

This is a genetic diagram illustrating the cross of parental generation and subsequent generations for seed color and shape in plants. - **Key**: - B: dominant allele for round seed - b: recessive allele for constricted seed - K: dominant allele for yellow seed - k: recessive allele for green seed - **Parental Generation (P)**: - Parental genotype: BBKK (round and yellow seed) crossed with bbkk (constricted and green seed) - Meiosis and fertilization result in F1 generation with genotype BbKk (round and yellow seed). - **F1 Generation**: - Self-crossed to produce F2 generation - Me

  • When the F1 generation produced from dihybrid cross was self-crossed, 16 F2 genotype combinations are produced.
  • The cross shows four phenotypic characteristics in F2 generation.
  • Outcome of the dihybrid cross is presented in a Punnett square as shown below.

This image is a Punnett square diagram used in genetics to predict the genotypes of offspring from a cross. It shows the combination of male and female gametes (BK, Bk, bK, bk) and their resulting phenotypes. The rows and columns represent different combinations of alleles for two traits: shape (round or constricted) and color (yellow or green). The resulting squares show the possible genotypes (BBKK, BBKk, BbKK, BbKk, bbKK, bbKk, bbkk) and their corresponding phenotypes (round yellow, round green, constricted yellow, constricted green).

The image shows a diagram illustrating the phenotypic ratio produced in the F2 generation of a genetic cross. There are four types of seeds displayed: 1. Round, yellow seed (9 parts) 2. Round, green seed (3 parts) 3. Constricted, yellow seed (3 parts) 4. Constricted, green seed (1 part) The phenotypic ratio is 9:3:3:1.
 
Mendel's Second Law

During gamete formation,each allele from a pair of alleles can combine randomly with any allele from another pair of allele.
 
The image is a slide summarizing Mendel's Dihybrid Experiment. It has a title ‘Summary of Mendel Dihybrid Experiment’ at the top. Below the title, there are two bullet points: 1. New combinations of characteristics are produced in the F2 generation, namely constricted yellow seed and round green seed. 2. Two characteristics (seed shape and color) are combined in the F1 generation but later they separate and react freely in the F2 generation. The background is white with a border of blue and orange shapes. The Pandai logo is at the bottom right corner.
 

 

 

 

 

The views expressed in the notes here are those of the contributor and don’t necessarily represent the views of Pandai.

Dihybrid Inheritance

 
11.2 Dihybrid Inheritance
 
Definition of Dihybrid Cross
Involves inheritance of two characteristics, each characteristic is controlled by a different gene located at a different locus.
 
Dihybrid Inheritance of Characteristics, Seed Shape and Colour Seed of Pea Plant 
  • The diagram below shows a schematic diagram of a dihybrid inheritance between two purebreed parents to study the characteristics of pea, namely seed colour and seed shape.
  • The two purebreed parents either have a pair of homozygous dominant alleles or a pair of homozygous recessive alleles.
  • Fertilisation between the two purebreed parents produce offsprings in F1 generation with the dominant traits of round and yellow seeds.

This is a genetic diagram illustrating the cross of parental generation and subsequent generations for seed color and shape in plants. - **Key**: - B: dominant allele for round seed - b: recessive allele for constricted seed - K: dominant allele for yellow seed - k: recessive allele for green seed - **Parental Generation (P)**: - Parental genotype: BBKK (round and yellow seed) crossed with bbkk (constricted and green seed) - Meiosis and fertilization result in F1 generation with genotype BbKk (round and yellow seed). - **F1 Generation**: - Self-crossed to produce F2 generation - Me

  • When the F1 generation produced from dihybrid cross was self-crossed, 16 F2 genotype combinations are produced.
  • The cross shows four phenotypic characteristics in F2 generation.
  • Outcome of the dihybrid cross is presented in a Punnett square as shown below.

This image is a Punnett square diagram used in genetics to predict the genotypes of offspring from a cross. It shows the combination of male and female gametes (BK, Bk, bK, bk) and their resulting phenotypes. The rows and columns represent different combinations of alleles for two traits: shape (round or constricted) and color (yellow or green). The resulting squares show the possible genotypes (BBKK, BBKk, BbKK, BbKk, bbKK, bbKk, bbkk) and their corresponding phenotypes (round yellow, round green, constricted yellow, constricted green).

The image shows a diagram illustrating the phenotypic ratio produced in the F2 generation of a genetic cross. There are four types of seeds displayed: 1. Round, yellow seed (9 parts) 2. Round, green seed (3 parts) 3. Constricted, yellow seed (3 parts) 4. Constricted, green seed (1 part) The phenotypic ratio is 9:3:3:1.
 
Mendel's Second Law

During gamete formation,each allele from a pair of alleles can combine randomly with any allele from another pair of allele.
 
The image is a slide summarizing Mendel's Dihybrid Experiment. It has a title ‘Summary of Mendel Dihybrid Experiment’ at the top. Below the title, there are two bullet points: 1. New combinations of characteristics are produced in the F2 generation, namely constricted yellow seed and round green seed. 2. Two characteristics (seed shape and color) are combined in the F1 generation but later they separate and react freely in the F2 generation. The background is white with a border of blue and orange shapes. The Pandai logo is at the bottom right corner.
 

 

 

 

 

The views expressed in the notes here are those of the contributor and don’t necessarily represent the views of Pandai.
Chapter : Inheritance
Topic : Describe Mendel's Second Law
Form 5 Biology
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