which one of the following is not a mendelian disorder
a) cystic fibrosis
b) pku
c) sickle cell syndrome
d) turnerss syndrome
Answers
Answer
d is your answer mark me as brainliest
Answer:
(D)
Explanation:
Hemoglobin has four protein subunits, two α-globin and two β-globin. The Hb
b
gene codes the β chain. Missense mutation, replacement of A by T at the 17th nucleotide of the Hb
b
gene changes the codon GAG (glutamic acid) to GTG (which encodes valine). The mutated alllele Hb
s
encodes the abnormal hemoglobin molecules which stick to one another and cause stiffness and sickle shape of red blood cells. The sickle shaped RBC block and damage the vital organs and tissue. The haemoglobin-β gene is located on chromosome 11 and the disease is inherited in an autosomal recessive manner.
Cystic fibrosis is caused by mutation in CFTR gene, present on long (q) arm of chromosome 7, codes for chloride channels. It is passed to progeny in autosomal recessive manner.
Haemophilia and colour blindness are genetic disorders because the governing genes are present of X-chromosome which is a sex chromosome in human. The traits are transmitted to offspring in a sex linked manner from mother to son and from father to daughters.
Mendelian disorders are controlled by a single locus and follow Mendel's laws of inheritance. All above mentioned disorders are caused by mutation in single gene locus and are inherited according to Mendel's law; hence these are Mendelian disorders. But Turner's syndrome is monosomy caused by absence of one copy of X-chromosome in females. These females carry only single copy of genes present on X-chromosomes and hence are sterile females. A female with Turner's syndrome produce 50% aneuploid gametes; thereby passing the disease to progeny. Here, single gene is not affected but the whole chromosome is missing; hence it is not a Mendelian disorder. Correct option is D