Module 4 Flashcards
(24 cards)
What is the most important but challenging aspect of studying genetic traits in humans?
Controlled matings are not possible, humans have a long generation time, and relatively few offspring are available for study.
What is a pedigree?
A pictorial representation of a family history that outlines the inheritance of one or more characteristics.
Who is referred to as the proband or propositus in a pedigree analysis?
The first affected person from whom the pedigree is traced.
What indicates consanguineous marriages in a pedigree?
Parents related or having common ancestors are connected by a double line.
List the applications of pedigree analysis.
- Identifies the pattern of inheritance
- Useful for genetic counseling
- Aids in predicting recurrent risks
- Helps predict genotypes in some cases.
What is autosomal inheritance?
A pattern of inheritance involving traits located on autosomes.
What are the two types of autosomal inheritance?
- Dominant
- Recessive
In autosomal dominant inheritance, who must be affected for an offspring to be affected?
Affected offspring must have an affected parent.
In autosomal recessive inheritance, what is a common occurrence in families with affected individuals?
Affected offspring are usually born to unaffected parents.
What is the inheritance pattern for autosomal dominant traits?
Vertical pattern of inheritance.
Provide examples of autosomal recessive traits.
- Albinism
- Cystic fibrosis
- Sickle cell anemia
- Attached earlobe
- Tay-Sach’s disease.
In X-linked dominant inheritance, how are affected sons and daughters related to affected parents?
Affected sons must have an affected mother; affected daughters must have an affected parent.
What is a characteristic feature of X-linked recessive inheritance?
More males than females are affected.
How are affected sons typically born in X-linked recessive inheritance?
Affected sons are usually born to unaffected mothers.
What is the pattern of inheritance for Y-linked traits?
Passed from affected father to all his sons, does not skip generations.
What is a new mutation in genetic terms?
A mutation that occurs in the germ cells of the parents or during early embryogenesis of the affected individual.
True or False: Autosomal recessive traits tend to skip generations.
True.
List examples of X-linked recessive disorders.
- Color blindness
- Classical hemophilia.
What is the inheritance pattern for autosomal dominant traits in terms of gender?
Appears in both sexes with equal frequency.
In X-linked dominant inheritance, how do affected heterozygous females typically present?
They are mildly and variably affected due to dosage compensation.
What is the characteristic of a pedigree that indicates a trait is autosomal recessive?
Horizontal pattern of inheritance, seen in siblings.
What is the significance of consanguineous marriages regarding genetic disorders?
They appear more frequently among the children of consanguineous marriages.
What is a unique characteristic of Y-linked inheritance?
It is relatively rare compared to other patterns of inheritance.
Example of sex influenced trait
Pattern baldness
