Genetics Flashcards
genotype
genetic information for trait
phenotype
observable trait
dominant gene
influences phenotype
recessive gene
present but not expressed
homozygous
inheriting the same form of gene for a given trait from both parents
heterozygous
inheriting different forms of the gene from both parents
incomplete dominance
slight influences from recessive gene (e.g. sickle-cell anaemia)
two types of chromosomal disorders
- sex chromosome disorders
- disorder on the 21st chromosome
x-linked inheritance
males at a greater risk of genetic disorders including learning and intellectual disabilities
sex chromosome disorders
may have an extra X (XXX or XXY) or only one X
two main types
- leads to cognitive deficits, intellectual disability, learning disorders and/or a speech impairment
- abnormality in reproductive system at puberty, can be treated with hormone supplements
fragile X syndrome
- gene is damaged on the x chromosome
- mild to moderate intellectual disability
- distinctive physical features
21st chromosome disorder
down syndrome
- lower life expectancy
- cognitive deficits (speech problem, intellectual disorders)
- mothers age increases chances
monozygotic vs. dizygotic
identical twins, shared placenta
vs.
fraternal twins, seperate placenta
epigensis
continuous bidirectional relationship
3 types of genotype -> environment effects
- passive genotype -> environment effects
- parents provide genes & environment to child
- evocative genotype -> environment effects
- person inherited characteristics evoke response from others in environment
- active genotype -> environment effects
- people seek out environment that correspond to genotyping characteristic
