Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
16 Cards in this Set
- Front
- Back
|
DNA |
deoxyribose nucleic acid - carry the genetic code that determines the characteristics of a living thing. - transmitted generation to generation - molecular structure described as a double helix |
|
|
Genes |
- short section of DNA
- Each gene codes for a specific protein by specifying the order in which amino acids must be joined together. |
|
|
Chromosomes: |
- Located in the nucleus
- made from long DNA molecules - humans have 23 pairs of chromosomes |
|
|
Alleles: |
- Different forms of the same gene (aka possibilities)
- e.g. gene for hair colour = black, brown, blonde, ginger variations
- Alleles can either be recessive or dominant (recessive alleles - need to be present on both sides to manifest)
Genotype: alleles in an organism i.e. Aa and AA have different genotype Phenotype: what organism looks like i.e aA + AA have same phenotype |
|
|
Homozygous and heterozygous |
1. Homozygous dominant: organism carries 2 copies of the same dominant alleles e.g. AA 2. Homozygous recessive: organism carries two copies of same recessive alleles e.g. aa 3. Heterozygous: has 2 different alleles of a gene e.g. Aa |
|
|
- constancy and variation |
1. somatic cell division: chromosomes are reproduced exactly - daughter cells are replicas of original
2. Gametogenesis: (creation of sex cells) - each pair of chromosomes form 4 different sex cells - randomizing parental genetic material >> fertilization: also creates variation as maternal + paternal genetic material combine - creates 46 chromosomes in next gen |
|
|
A code of DNAs bases |
- the pattern of A T G C (adenine,guanine, thiamine and cytosine) is a code for amino acids from which proteins are synthesized >> disruption to the genetic code (mutation - creates new genetic material) may affect different aspects of human communication |
|
|
- Types of inheritance |
1. Autosomal dominant inheritance: vertical transmission -50% chance of transmission 2. Autosomal recessive inheritance: horizontal pattern- carriers have 25% chance of transmission (co-consanguinity) 3. x- linked inheritance: associated with x-chromosomes + affects males, daughters are carriers 4. Mitochondrial inheritance: occurs only through mother via mitochondrial DNA in fertilized egg |
|
|
Genetic mutations which are linked to communication difficulties
|
- congenital hearing loss - inheritance of verbal dyspraxia (underlying SLI) - autism (ASD) > evidence for ASD inheritance = MZ twins high concurrence v DZ low rates |
|
|
importance of K+ in the endolymph |
CX 26 is essential for maintaining high K+ ion concentration in endolymph of inner ear 1. in response to vibrating ossicles in ME K+ in the endolymp >> hair cells (neural signal) 2. hair cell fires, system resets by the release of K+ to supporting cells Via cell gap junctions 3. released back to endolymph |
|
|
CX26 why mutations cause deafness |
- For k+ to pass through cells walls
- CX26 proteins provides channels between cells
- Mutations mean the CX26 channel doesn't open
- So highly k+ ion concentrations aren't maintained |
|
|
Congenital hearing loss and CX26 |
Mutations of the GJB2 gene that carries the code for CX26 is what causes congenital hearing loss
- it is the most common cause of autosomal recessive deafness |
|
|
Congenital hearing disorders: collagen mutation |
- Collagen is a tissue that strengthens bones
- Osteogenesis imperfecta - dominant mutation in one of the genes that produce collagen 1/2 - People with OI have weak bones - can affect ME ossicles >> Some carry the mutations but don't have symptoms at all |
|
|
> the inheritance of specific language impairment |
- genetics: SLI appears to run in families - concordance rates: MZ v DZ suggest SLI is genetic - KE family case study: suggest verbal dyspraxia is an autosomal dominant mutation of FOXP2 gene neuro-biology: reduced grey cells in inferior frontal gyrus (= Broca's area) - more than expected grey cells in Wernicke's area, angular gyrus and putamen |
|
|
Inheritance of Autism |
- mutations of specific genes increase likelihood of occurrence - 25% greater risk of child with autism if sibling is affected - siblings/parents are more likely to exhibit subtle ASD features - MZ twins 70-90% concordance v DZ twins 0-10% - highly likely to combined action of several interacting genes - synaptic dysfunction - popular dysfunction |
|
|
Evaluation |
- crucial disorder must be rigorously to begin - inherited factors may be subtle owing to variable expressivity or penetrance - complete picture = combination of linguistics/phonetics, genetics, biology + neurolinguistics |
