Tag: compatibility of blood groups

There are two main causes of erythroblastosis fetalis: Rh incompatibility and ABO incompatibility. Rh incompatibility occurs when a Rh-negative mother is impregnated by a Rh-positive father. The result can be a Rh-positive baby. In such a case, your baby’s Rh antigens will be perceived as foreign invaders, the way viruses or bacteria are perceived. Your blood cells attack the baby’s as a protective mechanism that can end up harming the child. If you’re pregnant with your first baby, Rh incompatibility isn’t as much of a concern. However, when the Rh-positive child is born, your body will create antibodies against the Rh factor. These antibodies will attack the blood cells if you ever become pregnant with another Rh-positive baby.

Erythroblastosis foetalis is a disease of the new born which is caused by Rh incompatibilty. This happens when mother is Rh negative and the child she is bearing is Rh positive. Thus the Rh antigen of child can trigger the antibodies inside mother which can travel through circulation thus destroying foetus blood cells. Thus, correct answer is option D.

Alleles are alternative forms of a gene. They are responsible for differences in phenotypic expression of a given trait. When a gene exists in three or more allelic forms it is called multiple allele. Homologous chromosomes are chromosome pairs, one from each parent. They are similar in length, gene position and centromere location. Multiple alleles are situated in homologous chromosome at the same locus. Thus the correct answer is option A.

Albinism is a autosomal genetical recessive gene disorder. It occurs in homozygous recessive state. The gene for albinism is a. it does not produce the enzyme tyrosinase, but is normal Allele A is does. Thus only homozygous individuals (aa) is affected. When both parents are albinic, all the offsprings also albinic generally.

So, the correct option is ‘Albino’.

When heterozygotes have a selective or reproductive advantage (overdominance or heterozygote advantage), alleles for both dominant and recessive traits are maintained in the gene pool, ensuring both homozygous genotypes continue to appear in future generations.

Multiple gene inheritance, also known as polygenic inheritance, involves traits controlled by two or more genes that typically show a continuous range of variation (continuous traits) rather than distinct categories.