Question

Mendel found that the reciprocal crosses yielded identical results. From that he concluded that
A. There is no dominance of any trait.
B. Sex has no influence on the dominance of traits.
C. There is an independent assortment of traits.
D. Sex plays a role in deciding the dominance of a trait.

Answer 1

Hint: The multicellular organisms have two sets of chromosomes that are received from both the parents during sexual reproduction. The organisms are known as diploid. The chromosomes occur in pairs and each pair is a set of homologous chromosomes. The traits or the characteristics are carried by the gene. Alleles are two or more forms of a given gene present on the same location on the chromosomes.

Complete answer:
Alleles are variations for a gene and result in expression of different characteristics. The alleles are exchanged from the parents to the offspring. An individual organism is known to contain two alleles for a particular gene that is received from the parents. In some cases, there sometimes occur changes which arise due to mutation.

The parental genes play an important role in the appearance of traits or characters in the offspring. The reciprocal cross explains and test the role of parental sex on the inheritance pattern of the traits or characteristics of the offspring. The concept of reciprocal cross causes the crossing between the pair of parents involved and by using them in turns as female and male parents. In other words, in this type of cross, the same genotypes are included as the first cross but their sexes are reversed. If in a first cross, the tall (male) is crossed with dwarf (female), then the reciprocal cross will be between tall (female) and dwarf (male). Thus, in this type of cross, the characters are the same but the sexes are opposite. The reciprocal cross is also known as the second cross.

The reciprocal cross is made to confirm the results that are obtained from the previous cross. The characteristics or traits that were utilised in the first cross are made to test again. The reciprocal cross shows the results obtained in the previous cross are same and identical. The results obtained through reciprocal cross confirm the outcome of the earlier crosses and there is no changes or effect due to the cytoplasm. The results of the reciprocal crosses show the dominance of one trait over the other trait which remains masked. The masked trait is known as the recessive gene. The dominance of certain traits are influenced by the sex of the parent and it can be said that the sex of the parent plays a role in the inheritance through reciprocal cross. The traits always segregate and show independence in expression.

Hence, The correct answer is option (B).

Note: The results of the reciprocal cross are compared with that of the previous cross and it shows the results as same as the other crosses. The deviation of inheritance results from reciprocal cross are due to the effect of cytoplasmic inheritance. The results shows that the sex of the parent influences the dominance of the traits that occurs in the offspring.