Table of Contents
Why is polydactyly a dominant trait?
If polydactyly is caused by just a single gene that only affects the number of fingers or toes and nothing else, then it is typically a dominant trait. If you have one “polydactyly” copy of any of these genes you get extra fingers even when the other copy says to make five fingers.
Is polydactyly a dominant or recessive trait?
Polydactyly is an abnormality characterized by extra fingers or toes. The condition may be present as part of a collection of abnormalities, or it may exist by itself. When polydactyly exhibits by itself, it is inherited as an autosomal dominant trait.
Is it true or false that polydactyly is an example of human dominant disorder?
Polydactyly is an inherited condition in which a person has extra fingers or toes. It is caused by a dominant allele of a gene. This means it can be passed on by just one allele from one parent if they have the disorder.
What gene is affected by polydactyly?
GLI3 gene mutations can cause several forms of isolated polydactyly. These include postaxial polydactyly type A (PAP-A) and type A/B (PAP-A/B), which are characterized by an extra digit next to the little finger or the small toe.
Why are some dominant traits uncommon?
One of the first things we’re taught in genetics is that some traits are dominant and others are recessive. Whether or not a trait is common has to do with how many copies of that gene version (or allele) are in the population. It has little or nothing to do with whether the trait is dominant or recessive.
Is polydactyly embryonic lethal?
Genetic elements suppress the polydactyl gene. Polydactyly is embryonic lethal.
Is polydactyly more common in males?
Polydactyly is twice as common among men. It occurs in 1 in 1,000 births in the general population. It’s found more frequently in the African American population, occurring in 1 in 150 births.
Are dominant traits always the most common Why or why not?
Dominant traits are the most common traits in a population. When people hear the word “dominant”, often they incorrectly believe that the majority of the population expresses this trait. Describing a trait as dominant does not mean it is the most common; it means that it is expressed over the recessive trait.
Is polydactyly fatal?
While polydactylism is not usually a life threatening condition, most parents want the condition treated to allow their child to live as normal a life as possible.
Why are some dominant traits not common?
Whether or not a trait is common has to do with how many copies of that gene version (or allele) are in the population. It has little or nothing to do with whether the trait is dominant or recessive. This isn’t because brown eyes are dominant over blue and green.