Tag: works of mendel

Pea plant has 2n= 14. Mendel chose 7 characters the genes for which are present on 7 different chromosomes. The presence of different chromosomes allowed genes for two traits to assort independently during dihybrid cross and recombinant progeny, as well as parental progeny, is produced. If he had chosen eight characters, genes for any two characters must be present on the same chromosome and would exhibit linkage and the law of independent assortment is violated. Law of dominance explains the appearance of a dominant trait by heterozygous genotype and law of segregation tells about segregation of alleles of heterozygous genotype during gamete formation. Law of purity tells about the presence of a single allele of a gene in gametes. Thus, the correct answer is option C.

• According to the law of dominance, a trait is represented by two contrasting factors of a gene in a heterozygous individual; only dominant trait is expressed, irrespective of the presence of both factors, in a heterozygous individual.
•  It does not tell about the reappearance of the missing trait in $F _2$ generation. The law of segregation states that the two factors for a trait, present together in a heterozygous individual, do not get mixed and are separated during gametogenesis. 
• Thus each gamete receives one allele for a trait and two types of gametes are formed; 50% gametes carry factor for dominance and 50% carry the recessive factor. Random fusion of these gametes leads to the presence of both recessive and dominant individuals in $F _2$ generation. 
• Law of independent assortment tells about segregation and distribution of factors governing two different traits; not about segregation of factors of one trait. Incomplete dominance is the condition when none of the factors of a gene is dominant and the phenotype of a heterozygous dominant individual is a blend of dominant and recessive traits. 
• It affects the phenotype of $F _1$ individuals, not that of $F _2$. Thus, the correct answer is option B.

Gregor Johann Mendel, an Austrian Monk, discovered the principles of heredity through the experiments on the pea plant. Mendel conducted hybridization experiments on garden peas for seven years and proposed the laws of inheritance in living organisms. They are the Law of dominance, Law of segregation, Law of Independent assortment.

So, the correct option is ‘Three’.

Gregor Johann Mendel, an Austrian Monk. He discovered the principles of heredity through the experiments on the pea plant. Mendel conducted hybridization experiments on garden peas for seven years and proposed the laws of inheritance in living organisms. They are Law of dominance, Law of segregation, Law of Independent assortment. He is regarded as Father of Genetics.

So, the correct option is ‘Mendel’,

He chose garden pea that was easy to grow and to hybridise artificailly.

The plant reproduce well and grows to maturity in a single season.

Mendel then chose to follow seven visible features(unit characters), each represented by two contrasting forms or traits.

Mendel was fortunate in choosing a diploid plant because diploid organisms contain only two sets of chromosomes.

A singe alteration in a trait was therefore demonstrated by a visible differences between varieites.

He restricted his examination to one or very few pairs of contrasting traits in each experiment.

He also kept accurate quatitative records, a necessity in genetic experiments.

In his experiments, no appearance of recombinations and linkage.

So, the correct option is ‘He did not encounter the linkage’.

The blending theory state that the inheritance of traits from two parents produces offspring with characteristics that are intermediate between those of the parents.

The incorrect pair here is the contrasting feature of the pod shape is "Elongated/constricted" which should be smooth/constricted in reality.