Final answer:
Different patterns of inheritance of genetic disorders can be identified by their characteristic expression in a pedigree. X-linked disorders often show gender bias, with X-linked recessive conditions more commonly expressed in males. Autosomal disorders require one or two copies of an allele to be expressed, depending on whether the disorder is dominant or recessive.
Step-by-step explanation:
To determine which mechanism of inheritance is presented in the pedigree, one must understand the main characteristics of different patterns of inheritance.
X-linked Dominant or Recessive Inheritance
An X-linked dominant pattern would typically affect more females than males because females have two X chromosomes and a dominant allele on one of them is sufficient to express the disorder. An X-linked recessive disorder is more commonly expressed in males because they only have one X chromosome, and a single recessive allele on this chromosome will express the disorder. Females would require two copies of the recessive allele to express the disorder and are often carriers if they only possess one copy.
Autosomal Dominant or Recessive Inheritance
An autosomal dominant disorder requires only one copy of the dominant allele for the disorder to be expressed, meaning an affected individual can inherit the disorder even if only one parent has the disorder. With an autosomal recessive disorder, affected individuals must have two copies of the recessive allele, typically one from each carrier parent. If both parents are carriers, there is a 25% chance that their child will be affected.