Genetics & Heritability Flashcards
D.O Hebb
• Genetic & environmental influences are entangled in complex ways
Behavior Genetics
Research to determine the degree of genetic basis for a behavior, trait
Behavioral genomics
Research that links behaviors with specific genes
Molecular genetics
How genes work with in the cell
What are the two laws of heredity?
- Shared genes
2. Gene pool
Mechanism of inheritance
• Chromosomes are made up of genes which are made up of DNA which is made up of 4 nitrogenous bases (1) guanine, (2) adenine, (3) thymine, (4) cytosine
Chormosomes
- 22 pairs of autosomes (mitosis)
* 1 pair of sex choromosomes (meiosis)
Alleles
location of a gene for a particular trait
Monozygotic twins
- one egg
- one zygote
- identical genetic make up
Dizygotic twins
- 2 eggs
- 2 sperms
- 2 zygote
- same genetic make up as siblings born seperately
Phenotype
- dominant genes expressed
* recessive gene only expressed when paired with another recessive gene
Genotype
•all of a persons genes both recessive & dominant
Mendelian Principles (old)
- Principles of dominance
- principle of segregation
- principle of independent assortment
Principle of dominance
• dominant & recessive genes
principle of segragation
Separated into reproductive cells
Principle of independent assortment
- gene that determines one characteristic is not dependent on a gene for another characteristics
- ex: all ppl with brown hair are not the same height
Mendelian current principles
- polygenic inheritance
- pleiotropic effects
- incomplete dominance
- codominance
- genomic imprinting
Polygenic inheritance
• MIXTURE of genes that will determine many characteristics
Pleiotropic effects
• any SINGLE gene can have many different effects
Incomplete dominance
- not COMPLETELY dominant or recessive
* ex: sickle cell anemia
Codominance
- When BOTH genes are expressed
* ex: AB blood type
Genomic imprinting
only one gene is expressed & the other is “silent”
What is the human genome project?
tba
Zygote
• fertilized egg that begins to divide into cells that will develop into the embryo
Chromosomes
• strands of genes that consitutes our existance
What is the human genome project?
• complete mapping and understanding of all the genes of human beings
Fragile x-syndrome
- Sex-linked
- Most common cause of intellectual disability
- 1 gene segment on the X chromosome is repeated 200x rather than 5-40x
Hemophilia
- Sex-linked
- Mostly males
- lack of a specific protein
- blood continues to flow
Huntington’s Disease
- Autosome-linked disorder
- dominant gene disorder
- chromosome 4
- lost of muscle control
- detected @ older age
Tay Sachs Disease
- Autosome-linked disorder
- onset about 8 months
- Chromosome 15
- death usually by age 6
- cell death, brain cells begin to die out
- loose motor skills, seizures, vision & hearing loss, intellectual disabled & paralysis.
Sickle Cell Anemia
- Autosome-linked disorders
- recessive gene
- incomplete dominance (can experience some symptoms)
- chromosome 11
- s or c shaped blood cells get clogged in the system
- shortness of breath, severe pain, characteristics similar to a stroke
- less likely to have malaria
Cystic Fibrosis
- Chromosome 7
- Autosomal recessive genetic condition
- affect lungs & digestive system
- life expectancy to early/mid-aulthood
- defective gene causes the fluids to become thick and sticky. Instead of acting as a lubricant, the secretions plug up tubes, ducts and passageways, especially in the lungs and pancreas.
Down-syndrome: trisomy-21
- having 3 “21” chromosomes
- Mental & physical defects
- life expectancy 60
- 1/1000
- higher risk to other diseases such as Alzheimer’s, cardiovascular issues
Autosome
• any chromosome that is not a sex chromosome
Sex chromosomes
• determining sex of organism
What are the ways to detect diseases prenatally?
- Amniocentesis
- CVS (chronic villus sampling)
- AFP (aplhafetoprotein)
- Ultrasound
Amniocentesis
- sample amniotic fluid
* screens for abnormality by measuring levels of feto protein & fetal cells as early as 16 wks
CVS (Chronic villus sampling)
- detects any chromosomal defects
- collect sample of fetal cells from placenta
- early as 9 wks
AFP
• measured through a blood test
Ultrasound
- sound waves
- screens for growth, organ defects, chromosomal abnormalities & neural tube defects
- checks if fetus is developing normally
Niche picking (scar & mccarthey)
- passive (parents make decision)
- evocative ( boys & girls respond diff. to env)
- active ( actively engaged in what they want to do, but the gene kind of predetermining what they should do)
- ex of active: tall male reared towards playing basketball, but he wants to play an instrument
Limit setting (gottesman)
- upper & lower limit (genetic)
- reaction rate (env)
- ex: genie had the genes to walk & talk, but the env she was in did not allow her to grow.
Non-shared enviornment
- Plomins model
- same genes, but env evokes diff response
- experience NOT shared w/ other members of the family.
