Genetics - Quiz

Gregor Johann Mendel, an Austrian monk, is recognized as the Father of Genetics for his groundbreaking work on inheritance. In 1856, he published his findings on the principles of inheritance, which are now known as Mendel's laws. Although his work was initially overlooked, it was rediscovered by three biologists in 1900.

The semidominant allele produces its biochemical products in lesser quantity in comparison to a dominant allele. Thus the heterozygote is of intermediate intensity. For example, the cross of a red and a white flower gives a pink flower.

Codominance is a type of inheritance where both alleles in a heterozygous individual are expressed equally. Unlike Mendelian inheritance, neither allele is dominant or recessive, and both traits are expressed in the offspring.

Epistasis is a type of gene interaction that involves the suppression of the effect of one gene by another non-allelic gene. It can result in the masking or modification of the expression of the gene. This type of interaction involves two pairs of alleles, and it can suppress both dominant or recessive alleles.

Pleiotropy is the term used to describe the condition where either a single gene has multiple functions in the body or two genes have the same expression of a single character. This means that two different genes can have the same effect on a single trait.

Pseudoalleles are two types of alleles that have similar functions but different structures. These genes are located in close proximity, and their similarity in function can lead to confusion in genetic analysis.

Linkage maps are constructed by using recombination frequencies between genes. Recombination is the process by which two homologous chromosomes exchange genetic material during meiosis. The frequency of recombination between two genes is proportional to the distance between them on the chromosome. Therefore, linkage maps can be constructed by measuring the recombination frequencies between genes.

Linkage is the tendency of two or more than two genes to stay together during inheritance. It can be broken by the process of homologous recombination, which occurs during crossing over in the pachytene stage of prophase I. This results in the exchange of genetic material between homologous chromosomes, leading to a new combination of alleles.

Sex-limited traits are those which occur only in one sex or the other. For example, milk production is limited to females while musculature is limited to males. However, baldness is a sex-influenced trait, which means that its expression depends on the sex of the individual and also on other factors such as hormones, genetics, and environmental factors. Baldness occurs more commonly in males than females, but it is not a sex-limited trait.

Pedigree analysis is the study of inheritance patterns for genetic traits in families over several generations. It involves constructing a diagram (pedigree) that shows the relationships among family members and the inheritance of the trait of interest. Pedigree analysis can be used to determine the mode of inheritance (autosomal dominant, autosomal recessive, X-linked dominant, X-linked recessive) and to predict the probability of an individual inheriting the trait.