Question

Match each term on the left with a statement on the right.

A.	Trait	1.	The genetic makeup of an individual
B.	Genotype	2.	A cross between an individual with an unknown genotype and a homozygous recessive individual
C.	Allele	3.	A variant for a character
D.	Testcross	4.	An alternative version of a gene
E.	Monohybrid cross	5.	A cross between individuals heterozygous for a single character

1. A – 3; B – 1; C – 4; D – 2; E - 5
2. A – 2; B – 3; C – 1; D – 5; E - 5
3. A – 5; B – 3; C – 4; D – 2; E - 1
4. A – 2; B – 1; C – 3; D – 4; E - 5

Answer 1

Correct Answer - Option 1 : A – 3; B – 1; C – 4; D – 2; E - 5

The correct answer is A – 3; B – 1; C – 4; D – 2; E - 5.

• Trait:
  • It is a specific characteristic of any organism.
  • It refers to any genetically determined characteristic of an organism.
  • It is variant for a definite character.
• Genotype:
  • It is the total sum of genes transferred to offspring by parents.
  • It is a set of heritable genes which are transferred between generations.
  • It is the unique genetic constitution of an organism or genetic makeup of an individual.
• Allele:
  • It is an alternative version of a gene.
  • Any organism inherits two alleles for each gene, one from each parent.
  • If both the alleles are the same, the individual is homozygous.
  •  If both the alleles are different, the individual is heterozygous.
• Testcross:
  • It is the breeding of specie with a recessive specie.
  • It was introduced by Gregor Mendel.
  • A cross between an individual with an unknown genotype and a homozygous recessive individual.
• Monohybrid cross:
  • A cross between individuals heterozygous for a single character.
  • It is a genetic mix between two individuals with homozygous genotypes which result in an opposite phenotype.

Notes:

• Dihybrid cross:
  • It is a cross between two different genes that differ in their observed traits.
  • It is a cross between two individuals that are heterozygous for two different traits.
• Difference between genotype and phenotype:

Genotype	Phenotype
It is the genetic makeup of an individual.	Visible characters are known as phenotypes.
The same genotype produces the same phenotype.	The same phenotype may or may not belong to the same genotype.
Inheritance from parents to the child.	Not inherited from the parent.
Determined by scientific methods like	Easily determined by observing the organism.
E.g  Blood group, eye colour, height, genetic diseases.	E.g Weight, physique

• Backcross:
  • It is a hybrid cross with one of its parents, or an adult genetically identical to the parent, to achieve offspring with a genetic identity closer to the parents.
  • It is used mainly in horticulture, animal breeding.