Question

In the pedigree below, what is the most likely mode of inheritance for this condition? X-linked dominant, X-linked recessive, autosomal dominant, or autosomal recessive? Affected individuals are shown as black symbols.

Based on your prediction, give the genotypes of the following individuals: I-1, I-2, II-1, II-3, II-4, III-1, III-2, III-4, IV-2, and IV-3. If you choose autosomal, use A or a; if you choose X-linked, use XA, Xa, or Y List the proposed genotypes of the designated individuals along the side:

I-1 1-2 1-2 II-1 II-2 II-3 11-4 II-1 II-3 II-4 III-1 III-2 III-4 IV-2 IV-3 III-1 III-2 III-3 III-4 III-5 ο IV-1 IV-2 IV-3 IV-4 IV-5 IV-6

Answer 1

The given Pedigree is an example of X- linked recessive type of inheritance because the males in the Pedigree is affected. It can not be Y- a linked type of inheritance because if the father is affected only then the trait is transmitted but when a cross is made between individual I-1 and II-2 here, in this case, the father is unaffected but the son is affected but this is not the condition of Y-linked type of inheritance.

It cannot be the autosomal recessive type of inheritance because as we can see that the only males are affected in this Pedigree but in autosomal recessive inheritance there is an equal probability of each sex being affected. It is different from X-linked recessive inheritance because here the gene is present on the autosomes so it should show themselves irrespective of sex but in case of X-linked recessive, it depends on sex because males have only one X chromosomes so the chances of males getting affected are 50% high as compared to the female.

So the given Pedigree is an example of X-linked recessive inheritance because if the male is affected and the parents are normal then the mother must be the carrier for the disease like individuals I-1, II-3 and III-2 are the carriers of X-linked recessive allele that produced affected male offsprings.

It can not be autosomal dominant or X-Linked dominant because in that case the individual 1 and individual 2 of the Ist generation produce an affected offspring but if the parents are recessive then they can not produce affected offsprings. So this condition is not possible.

when dor not Autosomal dominant is type of of inheritance enheritance in which is the affected gene present the autosomes and it is dominant then it generally skip generations The affected individuals will have genotype either or Aa The person have aa' will normal. genotype . AA مادیا be Auto pornal recessive It is a type of inneritance that will occur when both the allelelo are present en the recessive condition (aa). It is present on the auto fome will be the Heterozygous individuals for inheritance carrier this X-linked Inheritance It is of two x - linked dominant and typet X-linked recessure 7- linked the affected gene In dominant condition is present of pex chromosomes (X-chromosomes) Presence affected of x gene (only single) can cause the dis ease. x - linked is that occury are recessive type of inheritance when allelep prepent in recessive condition This wheritance is contain only X-Chromosome then if it is recessive then they will be affected. Presence of recessive alleles ein females will make them prevalent in malex because they one one

the carrier for the disease and presence of both will cause the disease in them recessive allele This where Y-chromo fome y linked enheritanice inheritance i present it transmits from offsprings all the affected father to male

XA Dominant xa - Recessive 2. T ХАх XAY 4 2. Ц. ху XAy х XAY 1 2 3 ІІ. хА у xxA XAY ху x*x* [x- 1 1 4 6 IV ху xay Carrier female - Normal fernale Affected male XAY - Normal male ху Affected male Normale female х х* carrier female Affected female x*x* XAY III - 2 XAY х* хя Normal male xxч 1 - 1 Ш. - 1 І - 2 П-1 ху - Хл х" ху - 4 Т - 7 у -2 ху ху у - 1 г-4 - ху