genetics

study of heredity and how traits are passed from one generation to the next

vertical gene transfer

genes inherited from parents and passed on to offspring through sexual reproduction

deoxyribonucleic acid (DNA)

the molecule all living organisms use to pass down geneticinformation,

universal language of genetics;

thin, threadlike and double stranded

histones

proteins which act as the 'spool' around which the thread of DNA is wrapped

ribonucleic acid (RNA)

cheap, single stranded molecule that can leave the nucleus; used to copy DNA information

chromosomes

single piece of coiled DNA containing many genes

diploid

having two homologous copies of each chromosome

homologous pairs

pairs of chromosomes, one of each from mothe/father  

alike in size, structure, and carry similar information

23 pairs in humans

 total of 46 chromosomes

central dogma of biology

DNA is used for a template to generate RNA in the process of transcription.

RNA codes for a specific sequence of amino acids that get linked together to form a protein;

this process is called translation

differentiation

process by which the body controls which genes are “turned on” to determine what type of function or role each cell will play

primary structure

string of amino acids determined by a DNA sequence

secondary structure

how the amino acids interact with one another

tertiary structure

shape of a protein, which determines it's function

quaternary structure

multiple proteins coming together as sub-units

phenotype

specific set of physical or observable characteristics, determined by interaction of genes and the environment

epigenetics

alteration of gene expression without actually changing DNA sequences

can be done in several ways (e.g. methylation)

methylation

Way genes can be turned off  and made

“transcriptionally inactive”

genomic imprinting

when genes inherited from the mother are methylated differently than genes inherited from the father; genes from either parent will be expressed differently

promoters

regions of DNA that do not code for proteins but rather promote transcription of specific genes

enhancers

regions of DNA that do not code for proteins but rather enhance transcription of specific genes

activators

proteins that increase rates of transcription by binding to promoter or enhancer regions

messenger RNA (mRNA)

RNA molecules that convey genetic information from DNA to the ribosome for translation into proteins

introns

regions of mRNA that are removed prior to translation into proteins

exons

regions of mRNA that are translated into a final protein; may be spliced together after removal of introns

mutations

random changes in the nucleotide sequence of DNA, ultimately resulting in  changes to the protein that is made.

Results of a mutation may be:

• a non-functional protein
•  no protein
• partially functional protein
• new protein
• no noticeable change in function of the protein

nucleotide

building blocks of DNA: G, A, T, or C

codon

3-nucleotide chain of DNA- codes for particular protein

insertion mutation

one or more nucleotides is inserted into the DNA sequence, causing a frame-shift mutation

deletion mutation

one or more nucleotides is deleted from the DNA sequence, causing a frame-shift mutation

frame-shift mutation

insertion/deletion (INDEL) mutations that causes a change in the “reading frame” and results in all codons after the mutations to be shifted and thus code for the wrong protein

substitution mutation

a “point mutation” that does not cause a frame shift but instead only alters that specific codon

Tin Man gene

mutation resulting in congenital heart defects in humans, and similar abnormalities in fruit flies

sexual reproduction

mode of reproduction where two parents contribute half of their DNA to produce a new, unique offspring, which gives rise to variation between individuals

alleles 

different versions of the same gene; in diploid organisms, one from the mother and one from the father are inherited. They are located at specific locations on each chromosome (loci)

loci 

specific locations of alleles on a chromosome

homozygous 

two identical alleles for a specific gene

heterozygous 

two different alleles for a specific gene

dominant allele

codes for a phenotype that masks or blocks recessive alleles, and so is always expressed and observed

recessive allele

codes for a phenotype that can only be expressed and seen when a dominant allele is not present

penetrance

whether or not you see the phenotype coded for in the genotype; if it is not expressed it is called incomplete penetrance

expressivity

when a gene can be expressed to varying degrees

pleiotropy

where one gene can impact multiple phenotypes (e.g. sickle cell)

polygenic

where multiple genes influence a single phenotype (e.g. skin color)

epistasis

where one gene masks the expression of another gene phenotypically (e.g. eyeless mice)

hormones

compounds released by the endocrine system from endocrine glands, transported through the bloodstream to target cells

hormone receptor 

protein in cells that binds to specific hormones

testerone

male hormone that directs the body to make primary sex and

later secondary male sex characteristics

estrogen and progesterone 

female hormones that direct the body to make primary and secondary sex characteristics

cortisol

hormone released when the individual is under stress; increases blood pressure and blood sugar levels

adrenaline (epinephrine)

“fight or flight” hormone that increase activity of the sympathetic nervous system and allow the body to respond to dangerous stimulus

neurotransmitters chemicals released by the nervous system that act similarly to hormones; they communicate in synapses and there are about 50 different chemical types

chemicals released by the nervous system that act similarly to

hormones; they communicate in synapses and there are about 50 different chemical types

dopamine

neurotransmitter linked to motivation and drive

serotonin 

neurotransmitter with many roles, including removing stress, controling movement of GI tract, and improving mood

enzyme

specialized type of protein that catalyzes certain reactions

Monoamine Oxidase A (MAOA) 

enzyme that regulates the level of serotonin, associated with behavior

warrior gene

version of the MAOA gene which when coupled with abusive experiences in childhood may lead to an increase in violent behavior

hox genes

genes involved in building our body structure