Question

What is an example of a mendelian trait in humans?

Answer 1

Hint: The research carried out by Mendel on pea plants for understanding inheritance patterns grant a solid base for our current perception of single-gene diseases in humans. Mendelian or monogenic diseases are triggered via mutations in one gene. Sometimes, they run in families. Mendelian diseases are a result of a mutation at a single gene locus.

Complete answer:
To determine whether a disease associated gene is located on an autosome or on a sex chromosome, and whether a phenotype of related disease is dominant or recessive, pedigree analysis of large families with many affected individuals can be performed.
Mendel gave two laws of inheritance namely, the law of segregation and the law of independent assortment.
1. Law of segregation: Each individual possesses two alleles, one is given by the female parent and the other is given by the male parent. This law states that the two alleles of a character present in an individual do not get mixed up but remain separated from each other at the time of gametogenesis. The individual is homozygous if the two alleles are identical, and heterozygous if the two alleles are different.
2. Law of independent assortment: This law states that alleles of different characters assort independently of one another at the time of gametogenesis and get randomly rearranged at the time of fertilization. There is an equal chance of every possible combination of alleles for every gene.
Cystic fibrosis is a disorder that primarily influences the lungs and the digestive system. A man or woman struggling from this disorder produces a peculiar quantity of sticky mucus which can act as a blockage to the lungs and the pancreas.
Thalassemia is an example of X linked recessive disease. In this disorder, there is an imbalanced synthesis of generally alpha and beta globins of haemoglobin leading to haemolytic anaemia.
Phenylketonuria :This disease is caused due to the low metabolic breakdown of the amino acid phenylalanine. An individual suffering from phenylketonuria does not have the enzyme Phenylalanine Hydroxylase that converts phenylalanine to tyrosine. This leads to the accumulation of phenylalanine. If it is accumulated in cerebrospinal fluid, it will lead to mental retardation.

Note:
Heredity is a method in which organisms inherit characteristics from their parents. These characteristics can be structural, functional and behavioristic. Every character has a special set of traits. The characteristics which are transferred from father or mother to its offspring via the technique of fertilization are known as inherited traits.