What are gene mutations? How can they happen? What is meant by a recessive trait? Why will the offspring develop a disease if it inherits two copies of a mutated gene?

If one chromosome of the mother is mutated, and some other chromosome of the father is mutated, and the offspring inherits both the mutated chromosomes is there any problem? What if the same chromosome of the father and mother is mutated, and the offspring inherits both of them?

 Gene mutations can be defined as the change in the sequence of gene. A segment of DNA which codes for protein is termed as gene. If there is any change in the DNA then it is termed as gene mutation. It can happen by various means like UV radiations, certain chemicals etc.

A trait which is not able to express itself in presence of other trait is termed as recessive trait. 

If offspring inherent two copies of the mutated gene than offspring will not be able to make the protein coded by mutated gene as both the copies are mutated hence nonfunctional. So, offspring will develop disease in such case. 

If one chromosome of the mother is mutated, and some other chromosome of the father is mutated, and the offspring inherits both the mutated chromosomes then there will not be any problem as one copy of the gene is normal and functional. 

 If the same chromosome of the father and mother is mutated, and the offspring inherits both of them, then the offspring will develop disease or may not survive as he have both non functional copies of gene which can not synthesis proteins.