Chapter 2: Biological and Environmental Foundations Flashcards
Mitosis vs meiosis
- Mitosis - each cell has the same DNA as parents
- Meiosis - egg and sperm creation, different DNA between cells
Fertilization
Sperm and egg fuse to form a zygote (46 chromosomes, 23 pairs)
The ___ chromosome pair is the sex chromosome
23rd
Types of twins
- Dizygotic - 2 zygotes, share 50% of DNA
- Monozygotic - one zygote, identical
Types of genetic inheritance
Dominant-recessive, incomplete, polygenic, genomic imprinting
Dominant-recessive inheritance
Dominant is always expressed unless there are two recessive genes
Incomplete inheritance
Both genes influence, “blending”
Polygenic inheritance
Interactions of many genes
Genomic imprinting
Expression dependent on inheritance from mother or father
Huntington’s disease
Develop normally until 40, then develop symptoms. A neurodegenerative disorder.
Down syndrome
Additional chromosome on pair 21, leads to premature aging and decline of cognitive function. Associated with Alzheimer’s, developmental delays, change in facial shape.
Mutations are often ____ and caused by…
Fatal, exposure to toxins or spontaneous
Example of beneficial mutations
Sickle cell gene
Four components of genetic counseling
Risk determination, family history of heritable disorders, genetic screening blood tests, determining how to proceed
Examples of risk factors in reproduction
Women over 35, infertility
Types of reproductive technology
Artificial insemination, in vitro fertilization, surrogacy, prenatal selection
In vitro fertilization
Multiple eggs are harvested, but only one or two zygotes are transferred (50% survival rate)
Ethical concerns of surrogacy
It’s hard to give the baby up, creates a power dynamic between the classes
Types of prenatal selection
Pre-conception sperm sorting, pre-implantation genetic diagnosis
Problems with adoption
Expensive, more common in upper class, often unhealthy foster care
Methods of prenatal diagnosis
- Ultrasound
- Fetal MRI
- Noninvasive prenatal testing
- Amniocentesis
- Chorionic villus sampling
Noninvasive prenatal testing
Take a blood sample from the mother
Amniocentesis
Take a sample of amniotic fluid through the abdomen
Chorionic villus sampling
Take a sample of the membrane around the amniotic fluid through the vagina
Types of prenatal treatment
Fetoscopy, hormone and drug deliver, blood transfusions, surgical procedures, genetic engineering
Fetoscopy
Small camera that goes through the abdomen
Behavioral genetics
Heritability, family/twin studies, adoption studies
Gene-environment interactions
Range of reaction, canalization, gene-environment correlations, epigenome
Range of reaction
Range of a trait’s potential expression (ex. height), affected by environment
Canalization
Traits that have a more narrow range of development (ex. eye color)
Gene-environment correlations
Passive, reactive/evocative, active (niche-picking)
Epigenome
Determines if and how genes are expressed
