Describe Mendelian Disorder
Mendelian disorders are mainly determined by alteration or mutation in the single gene. These disorders are transmitted to the offspring on the same lines as we have studied in the principle of inheritance.
The pattern of inheritance of such Mendelian disorders can be traced in a family by the pedigree analysis.
Most common and prevalent Mendelian disorders are Haemophilia, Cystic fibrosis, Sickle-cell anaemia, Colour blindness, Phenylketonuria, Thalesemia, etc. It is important to mention here that such Mendelian disorders may be dominant or recessive.
By pedigree analysis one can easily understand whether the trait in question is dominant or recessive. Similarly, the trait may also be linked to the sex chromosome as in case of haemophilia.
It is evident that this $X-$linked recessive trait shows transmission from carrier female to male progeny. A representative pedigree is shown in Figure for dominant and recessive traits,
A normal woman, whose father was colour-blind is married to a normal man. The sons would be
Given below is a highly simplified representation of the human sex chromosomes from a karyotype.
The genes $a$ and $b$ could be of
In the given pedigree, indicate whether the shaded symbols indicate dominant or recessive allele.
Sex linked disease is
Which is correct for inheritance of autosome linked recessive gene?