Genetics Flashcards
Genotype vs phenotype
Genotype = genetic make-up, the letters
Phenotype = physical expression, what we can see
Describe Segregation. What happens if there’s an error in segregation?
2 alleles of 1 particular trait will be separated & distributed to 2 different daughter cells
ex: Jj; allele J will go to 1 daughter cell & allele j will go in other
Errors= cancer, infertility, down syndrome
What happens during crossover?
aka chiasma
homologous chromosomes can break, & cross over resulting in recombinant chromosomes (mixture of combos from each parent)
Describe incomplete dominance. An example?
heterozygous indiviuals have intermediate phenotype
they might have sxs but not as intense
ex: sickle cell
Multiple-allele inheritance example?
Blood typing
genes that exhibit 1+ allele
Describe sex-linked inheritance
inherited traits determined by genes on sex chromosomes (XX or XY)
X chromosomes bear over _____ genes while Y chromosomes carry about ____
X = 1400+
Y = 200
Genes found only on X chromosome are called
X-linked genes
X-linked RECESSIVE alleles are ALWAYS expressed in _____
males; bc there is no Y counterpart
Females must have recessive alleles on_______ in order to express an X-linked condition
both X chromosomes
What conditions are passes from mothers to sons? (hemophilia, red-green color blindness)
X-linked recessive conditions
A female who is a carrier (heterozygous) for red-green color blindness + male w normal color vision are going to have a boy baby.
What is the % of the boy having colorblindness?
50%
A female who is a carrier (heterozygous) for red-green color blindness + male w normal color vision are going to have a boy baby.
What is the % of the offspring having colorblindness?
25%
A female who is a carrier (heterozygous) for red-green color blindness + male w normal color vision are going to have a boy baby.
What is the % of the female baby being a carrier of colorblindness?
50%
Name the 3 levels of control found in the human genome
1st layer: protein coding genes
2nd layer: small noncoding RNAs
3rd layer: epigenetic marks
The 1st layer of control involves ____ & is involved in what % of a cell’s DNA?
“protein coding genes”
DNA that is “blue print” for protein synthesis, that is actually synthesized
less than 2%
The 2nd layer of control is found ____ & is involved in what % of a cell’s DNA?
“small noncoding RNAs”
non-protein-coding DNA
80% of genome
The 3rd layer of control is stored in ____ that binds to ____ & affects what?
“epigenetic marks”
stored in proteins & chemical groups
binds to DNA
affects how chromatin are packaged
All DNA is in the
nucleus
The most common small noncoding RNA is
microRNAs (miRNAs)
Small noncoding RNA function
reduce expression of particular genes
joins w enzymes to silence genes
What are transposons & what inactivates them? When is it important?
genes that tend to replicate themselves & insert themselves into distant DNA sites = disabling or hyper-activating genes
small non-coding RNAs inactivates
normally during development, fight off viral infections
Mutations in sncRNAs have been implicated in
cancers & schizophrenia
Certain chemical tags determine whether DNA is available for transcription (____) or silenced (______)
transcription = acetylation
Silenced = methylation
