A feature of a pedigree that indicate that a certain trait is a dominant trait is that one of the parents always have to have the trait.
There are, however, autosomal dominance and X-linked dominance.
For an autosomal dominant trait: - Appears equally frequent in both sexes. - Both sexes transmit the trait. - Present in all generations. - When one parent has the trait and the other doesn't, approximately half of the offspring will present the trait.
For a X-linked dominant trait: - Both male and females can present the trait, but more females usually present it. - Sons with the trait always have a mother that presents the trait as well. - Daughters with the trait always have either a mother or father that presents the trait, or both. - Fathers with the trait always have daughters with the same trait.
The trait will be shown more frequently in the family pedigree. Rest of the characteristics will depend on whether it is an autosomal or X linked dominant trait.
Explanation:
A pedigree analysis is used to study inheritance of genes in a family. It is used for many purposes like finding out the genetic source of a disorder in family or predicting the trait outcome for future progeny based on status of family members. If it's a dominant trait, it would be expressed even with a single copy so such a pedigree shows the trait more frequently.
Further Explanation:
Autosomal dominant trait:
An autosomal dominant trait will express itself in both the sexes.
Both the sexes will pass on the trait.
Overall pedigree will have at least one affected member in every generation because it is dominant and sex independent.
If around half of the children are affected and one parent is unaffected that means other parent is affected and heterozygous for the trait .
X-linked dominant trait:
A X linked dominant trait will be more frequently presented by a female.
A son with the trait will always have a mother with the trait because he inherited X chromosome from the mother.
Daughter with the trait will have either one or both the parents affected by the trait.
Fathers who have this trait will always have daughters with this trait becuase they will pass surely one X chromosome to the daughter.
North component: y = 15.0 m * sin 55.0º = 12.3 m West component: x = 15.0 m * cos 55.0º + 7.00 m = 15.6 m so his heading, measured from West, is Θ = arctan(y/x) = arctan0.787 = 38.2º N of West and measured from North is φ = arctan(x/y) = arctan(1.27) = 51.8º W of North Hope this helps!
