Exam 2 Flashcards
Genetics and Stuttering
Genotype
Specific genetic constitution in one or several sites.
Genetics and Stuttering
Phenotype
Realization of observable characteristics
Genetics and Stuttering
Penetrance
The likelihood that a person with a specific gene will show that gene’s effects. i. Development of phenotypes is not an all or nothing phenomena.
Genetics and Stuttering
Pleiotropy
Multiple effects of a gene
Genetics and Stuttering
Variable expressivity
Extent or manner of expression (mild to severe across people or time or as different traits across time)
Genetics and Stuttering
Reaction range
Qualitatively and quantitatively different phenotypes that can develop from the same genotype under varying environmental conditions.
- Each genotype has a specific range of phenotypes that can develop
- A phenotype within that range develops because of environmental interactions that occur throughout development
Genetics and Stuttering
Possible relationships of genotypes and phenotypes (3)
- Different genotypes can produce different phenotypes
- Different genotypes can produce phenotypes that are indistinguishable (genetic heterogeneity)
- Same genotypes can produce more than one phenotype, sometimes depending on environmental conditions (pleiotropy and variable expressivity)
Genetics and Stuttering
Realization of a function specified in segments of DNA is dependent on what?
- On metabolic system of cell
- Which is dependent on the whole organism
- Which is dependent on the physical and social environment needed for the organism’s development
- Thus, we cannot say if genetic constitution or environment is more important.
Genetics and Stuttering
Genetic Models in stuttering (3)
- Monogenetic
- Polygenetic
- Mixed
Genetics and Stuttering
Genetic Model: Monogenetic
Single gene is implicated in the transmission of stuttering.
Genetics and Stuttering
Genetic Model: Polygenetic
Cumulative effects of multiple, unrelated genes. Would result in a normal distribution of fluency skills.
Genetics and Stuttering
Genetic Model: Mixed
Both a single gene and the effects of other genes are implicated in transmission.
Genetics and Stuttering
What are the simple genetic transmission patterns? (3)
- Dominant
- Recessive
- Sex-linked recessive
Genetics and Stuttering
Simple genetic transmission patterns: dominant
Presence of one gene in the gene pair causes expression of the trait.
- High incidence form parent to child
- Too low of an incidence among relatives to fit this.
- Example: Huntington’s Chorea
Genetics and Stuttering
Simple genetic transmission patterns: recessive
Effects of one gene are subordinate to the other in the pair. Need both to cause the effects.
- Example: Brown eyes = dominant, blue eyes = recessive
- Trait less often in parents than in affected child’s siblings
- This is not the case with stutterers.
- Near equal incidence for siblings and offspring
Genetics and Stuttering
Simple genetic transmission patterns: sex-linked recessive
Recessive transmission linked to the chromosomes determining gender.
- Rarely transmitted from father to son (e.g., hemophilia)
- High frequency of rather to son transmission in stuttering
Genetics and Stutterin
Do transmission patterns in stuttering fit simple transmission patterns
Patterns of incidence in families of stutterers do not fit these patterns of genetic transmission.
Operant Methodology
Operant
Future occurrences of behavior are a function of its consequences
Operant Methodology
Reinforcement
Reinforcement increases the behavior
- Positive reinforcement - presentation
- Presented after behavior
- Negative reinforcement - withdrawal
- Withheld/removed after behavior
Operant Methodology
Punishment
Punishment after behavior decreases the behavior
- Type 1 - presentation
- Example: person stutters, electric shock is given, stutter decreases
- Type 2 - withdrawal
- Example: person stutters, clinician uses time-out (withdraws the person-to-person interaction), stutter decreases