Phenotype and Genotype Flashcards
(10 cards)
What are genetic disorders?
Are disorders caused by gene transmission from one generation to another (vertically) but not in the same generation like viral or bacterial infections.
What is albinism and what is its cause?
Albinism is due to the absence of pigmentation of skin hair and eyes. It is caused by the absence of melanin.
What is the metabolic pathway?
Food ➡ Phenylaline ➡(E1) Tyrosine ➡(E2) Melanin
What would happen if any aberration occured in E1 and E2?
will lead to absence of melanin and cause albinism
What are E1 and E2?
are protein enzymes coded by genes located on an autosome thus the transmission of albinism is autosomal recessive.
What does autosomal mean?
Located on an autosome (ch.1➡22) affect boys and girls equally well.
What does recessive mean?
only expressed in the homozygous state (pure race) that is an individual should possess two deceased alleles to be affected (d//d)
What is sickle cell anemia?
also an autosomal recessive trait it is due to the formation of an abnormal hemoglobin HbS like the normal hemoglobin HbA, HbS transports O2 to the tissues but once O2 is released hbs becomes insoluble and precipitates in the cell changing its structure and causing its death
What does sickle cell anemia lead to?
decreased numbers of RBC’s (anemia) and increased risk of infarction
What is Duchenne muscular dystrophy?
it is caused by the lack of dystrophyn a protein that gives the muscle it’s integrity.This disease affects mainly boys and thus it is sex linked (gonosomal).The Gene which determines the disorder is located on chromosome x and thus the affected boy inherits it from his carrier mother (recall that he inherits the Y chromosome from his father)
