Chapter 6 Vocab Flashcards
What is a pedigree?
A pedigree is a pictorial representation of a family history, essentially a family tree that outlines the inheritance of one or more characteristics.
List characteristics of an Autosomal Dominant Trait
- Appears in both sexes with equal frequency.
- Both sexes transmit the trait to their offspring.
- Does not skip generations.
- Affected offspring must have an affected parent, unless they possess a new mutation.
- When one parent is affected (heterozygous) and the other parent is unaffected, approximately 1⁄2 of the offspring will be affected.
- Unaffected parents do not transmit the trait.
- Appears in both sexes with equal frequency.
- Both sexes transmit the trait to their offspring.
- Does not skip generations.
- Affected offspring must have an affected parent, unless they possess a new mutation.
- When one parent is affected (heterozygous) and the other parent is unaffected, approximately 1⁄2 of the offspring will be affected.
- Unaffected parents do not transmit the trait.
Autosomal Dominant Trait
List characteristics of an Autosomal Recessive Trait
- Appears in both sexes with equal frequency.
- Trait tends to skip generations.
- Affected offspring are usually born to unaffected parents.
- When both parents are heterozygous, approximately 1⁄4 of the offspring will be affected.
- Appears more frequently among children of consanguine marriages.
- Appears in both sexes with equal frequency.
- Trait tends to skip generations.
- Affected offspring are usually born to unaffected parents.
- When both parents are heterozygous, approximately 1⁄4 of the offspring will be affected.
- Appears more frequently among children of consanguine marriages.
Autosomal Recessive Trait
List characteristics of an X-Linked Recessive Trait
• More males than females are affected.
• Affected sons are usually born to unaffected mothers;
thus, the trait skips generations.
• Approximately 1⁄2 of a carrier (heterozygous) mother s sons are affected.
• It is never passed from father to son.
• All daughters of affected fathers are carriers.
• More males than females are affected.
• Affected sons are usually born to unaffected mothers;
thus, the trait skips generations.
• Approximately 1⁄2 of a carrier (heterozygous) mother s sons are affected.
• It is never passed from father to son.
• All daughters of affected fathers are carriers.
X-Linked Recessive Trait
List characteristics of an X-Linked Dominant Trait
• Both males and females are affected; more often females than males affected.
• Does not skip generations.
– affected sons must have an affected mother
– affected daughters must have either an affected mother or an affected father.
• Affected fathers will pass the trait on to all their daughters.
• Affected mothers (if heterozygous) will pass the trait on to 1⁄2 of their sons and 1⁄2 of their daughters.
• Both males and females are affected; more often females than males affected.
• Does not skip generations.
– affected sons must have an affected mother
– affected daughters must have either an affected mother or an affected father.
• Affected fathers will pass the trait on to all their daughters.
• Affected mothers (if heterozygous) will pass the trait on to 1⁄2 of their sons and 1⁄2 of their daughters.
List characteristics of an X-Linked Dominant Trait
List characteristics of an Y-Linked Trait
- Only males are affected.
* It is passed from father to all sons. • It does not skip generations.
- Only males are affected.
* It is passed from father to all sons. • It does not skip generations.
Y-Linked Trait
Monozygotic twins
result when a single egg, fertilized by a single sperm, splits early in development into two separate embryos. (Identical twins, 100% genes shared)
result when a single egg, fertilized by a single sperm, splits early in development into two separate embryos. (Identical twins, 100% genes shared)
Monozygotic twins
Dizygotic twins
arise when two separate eggs are fertilized by two different sperm, producing genetically distinct zygotes. (Non-identical twins, 50% genes shared, same as any pair of siblings.
arise when two separate eggs are fertilized by two different sperm, producing genetically distinct zygotes. (Non-identical twins, 50% genes shared, same as any pair of siblings.
dizygotic twins
If both members of a twin pair have a trait, the twins are said to be ______________
concordant
If only one member of a twin pair have a trait, the twins are said to be ______________.
discordant
___________________ is the percentage of twin pairs that are concordant for a trait.
concordance
Genetically influenced traits should exhibit higher concordance in monozygotic twins, because _______
identical twins (monozygotic) have 100% of their genes in common and dizygotic twins on average only 50% in common
What is genetic testing used for?
– screen newborns for genetic diseases,
– detect persons who are heterozygous for recessive diseases
– detect disease-causing alleles in those who have not yet developed symptoms of the disease
– detect defective alleles in unborn babies.
