Females are usually carriers because they only have one copy of the disease allele. Affected males are related through carrier females. For a carrier female, with each pregnancy there is a one in two (50%) chance her sons will inherit the disease allele and a one in two (50%) chance her daughters will be carriers.
A complimentary close, also known as a complimentary closing, is the term prior to your signature in an email message or formal letter. This sign-off phrase shows your respect and appreciation for the person who is considering the request in your letter or email.
Main Difference: The main difference between a formal letter and an informal letter is their purpose: a formal letter is written for professional (official and business) communication while the informal letter is used for personal communication. A letter is a written message from one party to another containing information.