genetic methods Flashcards
what is genetic research?
- study of heredity
- how traits are passed from generation to generation
define genotype
- underlying biological makeup
define phenotype
- observable traits
who is Gregor Mendel?
- cited to be the first geneticist
define dominant
- traits that only require one allele to be expressed
- these will be the organisms phenotype
define recessive
- requires two alleles to be expressed
- only expressed when there is no dominant trait
define allele
- version of a gene
- either dominant or recessive
what 2 fundamental laws does Mendelian inheritance rely on?
1/ segregation
- traits either dominant or recessive
2/ independence
- varieties of each trait sort independently of each other
where is DNA found?
- nucleus
what is DNA composed of?
- 2 chains of nucleotides
- these coil around each other
- forms double helix
what does the double helix contain?
- genetic instructions for development, functioning, growth, reproduction of all known biological organisms
how are protein strands made?
- double helix = unzipped
- read by RNA molecules
- process = translation
what are the 4 bases?
Adenine
Guanine
Cytosine
Thymine
define chromatids
- long strand of DNA
- found in nucleus
- coil during cell division to form chromosome
describe what happens to chromatids during cell division
(DNA to chromosome)
- chromatids undergo condensation
- coil together
- forming chromosome
how many chromosome in a typical human?
46 (23 pairs)
what are all pairs of chromosome aside from one?
- all are XX
- final pair varies
what does the final pair of chromosomes code for?
- biological sex
- either XX or XY
define gene
- describes single strand of functional DNA on a chromosome
how many genes do humans possess?
between 20,000 to 25,000
define genome
a collection of genes
define pleiotropic
- where phenotypic traits = programmed by single gene
define polygenic
- where phenotypic traits = influenced by combination of genes
why study genetics?
- help understand genetic disorders
- greater understanding of biology
what are X-linked genes
- where some recessive traits more commonly expressed in males compared to females
- due to males not having a dominant allele on their (much shorter) Y chromosome
what are sporadic mutations?
- occurs as a result of errors in typical cell division
- mutations happen naturally
- or mutations happen as result of environmental factors (e.g.: radiation)
what are polygenic traits?
- traits that rely on coding from multiple genes
- may not follow Mendelian rules
- many genetic disorders considered to be polygenic in nature
give examples of X-linked genetic disorders
- colourblindness
- Turner Syndrome (effect females with only one X chromosome)
- Klinefelter Syndrome (effects males with additional X chromosome)
- Fragile X syndrome
give example of genetic disorder that occurs due to sporadic mutation
Down’s Syndrome
- extra chromosome
(due to errors in segregation of alleles)
Williams Syndrome
- due to micro-deletion on chromosome 7
give example of genetic disorder that occurs due to polygenic traits
schizophrenia
- not a single gene causes this
- but individual considered to be genetically predisposed to develop this (may have trait but not show signs of it)
- has clear genetic link
how have genetic conditions been studied?
- twin studies
- monozygotic twins = twins from same egg, 100% share DNA (genetically identical)
- dizygotic twins = twins from separate egg, 50% DNA
what are genomic studies?
- inspects genome of specific groups
- help identify allele commonalities (looking at what is consistent across them)
what are targeted mutations?
- mutated lab produced genes inserted into chromosomes
- there are two types
what are the two types of mutated lab produced genes that are inserted into chromosomes?
- knockout genes
- knock-in genes
what are knockout genes?
- mutated lab produced genes that fail to produce specific functional protein
what are knock-in genes?
- mutated lab produced genes that can produce specific functional protein
what is genetic engineering?
- where we can edit our own genome
- currently being used to tackle HIV and cancer
