Question

Brachydactyly type d is a human autosomal dominant condition in which the thumbs are abnormally short and broad. in most cases, both thumbs are affected, but occasionally just one thumb is involved. the accompanying pedigree shows a family in which brachydactyly type d is segregating. filled circles and squares represent females and males who have involvement of both thumbs. half-filled symbols represent family members with just one thumb affected.

Answer 1

A. The term variable expressivity refers to the differences that can be observed in the phenotype of individuals with the same genotype. This phenomenon can explain the range of signs and symptoms seen in people with the same genotype. The pedigree provided shows that the family has individuals with one affected thumb and individuals with two affected thumbs. These individuals have the same genetic condition but their symptoms are different and this means that there is evidence for variable expressivity of this specific genetic trait in this family.

B. There are cases where an individual carries a specific gene but does not express the phenotype connected to this gene. This phenomenon is called incomplete penetrance. The pedigree shows that unaffected parents (III-5 and III-10), have affected children who express the trait. This means that these parents carry the autosomal allele for this trait and passed on to their offsprings.

Answer 2

A hereditary characteristic, brachydactyly type D shows autosomal predominance and is regularly created or acquired freely of other genetic qualities. The condition is related to the HOXD13 quality, which is main in digital formation and development.

Further explanation

Brachydactyly

Brachydactyly is a shortening of the fingers and toes because of curiously short bones. This is an acquired condition, and much of the time does not present any issues for the individual who has it. There are various kinds of brachydactyly, in view of which bones are abbreviated. This condition can likewise be a side effect of another hereditary issue. Except if there is a going with confusion that produces side effects, or the abbreviated digits weaken the utilization of hands and feet, there is no treatment required for brachydactyly. Most common type of brachydactyly is d type.  In this type end bones of the thumbs are shortened.

Symptoms

The indications of brachydactyly are generally present during childbirth, however, it's conceivable that abbreviated appendages become increasingly evident with development and advancement. The fundamental symptoms of brachydactyly are fingers, toes, or both that are shorter than typical. Surgery is the only solution for this.  

Reasons behind brachydactyly

It is an autosomal dominant disorder, which means you just need one parent with the quality to acquire the condition. It's idea that two distinct transformations in a specific quality add to brachydactyly. Now and again, it's conceivable that brachydactyly is brought about by medicines that the mother takes during pregnancy. It might likewise be brought about by bloodstream issues to the hand and feet, particularly in newborns. Brachydactyly D is symptomatic of a hereditary disorder. This may be due to incomplete dominance.

Answer details

Subject: Biology

Level: College

Keywords

• Brachydactyly
• Symptoms
• Reasons behind brachydactyly

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