A40-year-old, blond, blue-eyed woman has found an irregular, brown-pigmented lesion on her shoulder. she admits enjoying the sun and outdoor activities. a biopsy shows the lesion is malignant.
what is the embryonic origin of the cells that gave rise to this malignancy?

a. neural crest
b. dermatomal mesoderm
c. ectoderm
d. intermediate mesoderm
e. lateral mesoderm

Neural crest -  

Explanation:

Neural crest -  

The neural crest is those temporary sets of cells that are stick to particular vertebrates that arise due to the embryonic layer of germs. Neural crest provides a way to produce PNS(peripheral nervous system).

These cells are migratory cells that can develop into different cells tissue all over the body.

an individual’s sex (i.e., whether they are a male or female) is determined by the sex chromosomes. most people have two sex chromosomes, one that is inherited from their mother and one that is inherited from their father. typically, females have two x chromosomes (xx) and males have one x chromosome and one y chromosome (xy). conditions caused by changes (“mutations”) in genes located on the x chromosome are considered x-linked.

x-linked recessive inheritance

most x-linked conditions are recessive. this means that in a person with two x chromosomes (most females), both copies of a gene (i.e., one on each x chromosome) must have a change or mutation whereas in a person with one x chromosome (most males), only one copy of a gene must have a mutation. a female with a mutation in one copy of a gene on the x chromosome is said to be a “carrier” for an x-linked condition. a male with a mutation in a gene on the x chromosome is typically affected with the condition. because females have two copies of the x chromosome and males have only one x chromosome, x-linked recessive diseases are more common among males than females. however, x-linked recessive diseases can occur in both males and females.

for x-linked recessive disorders, an unaffected carrier mother who has a mutation in a gene on the x chromosome can transmit either the x chromosome with this mutation or a “normal” x chromosome to her children. if the father is unaffected, none of her daughters will be affected and all of her daughters will be unaffected—since they will inherit at least one normal x chromosome from their father. however, each daughter will have a 50% chance of being an unaffected carrier like her mother and a 50% chance of both x chromosomes being normal.