Term
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Definition
| causes death before individual can produce; early lethal alleles cause embryonic death |
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Term
| Lethal recessive alleles result in ___ |
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Definition
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Term
| Describe a compound heterozygote |
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Definition
| someone with 2 different mutant alleles for the same gene |
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Term
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Definition
| neither allele is dominant over the other; both are fully expressed (type AB blood) |
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Term
| Parents with tyep A and B blood can have a child with what blood type? |
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Definition
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Term
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Definition
| one gene blocks the expression of another (coat color) |
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Term
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Definition
| all or none expression of a genotype; number of ppl who express the gene/those who inherited the allele |
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Term
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Definition
| severity or extent of a phenotype; occurs when symptoms vary from person to person |
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Term
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Definition
| make different phenotypes from single genotype |
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Term
| Describe genetic heterogeneity |
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Definition
| mutations in different genes that make the same phenotype; different routes to the same endpoint |
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Term
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Definition
| closed mini chromosome with 37 genes; no crossing over; only inherited from mother; no space between genes |
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Term
| Describe mitochondrial disorders |
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Definition
| inherited from maternal line only, mutations usually occur in high E demanding tissues major symptoms are weakness and fatigue |
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Term
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Definition
| condition where some mt chromosomes have mutation and others do not; references mt only |
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Term
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Definition
| condition where all mt have mutation; embryos do not develop |
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Term
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Definition
| located near each other on same chromosome, do not segregate independently, tends to be inherited together, physically linked |
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Term
| Describe genetic distance in linked genes |
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Definition
| measured by recombination frequency, the further apart 2 loci are the more recombinations observed (may behave as unlinked) |
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Term
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Definition
| progeny that show mixing of parental alleles on single chromosome |
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Term
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Definition
| environmentally caused trait that appears to be inherited |
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Term
| If the SRY gene on the y chromosome is active, the child is ____ |
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Definition
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Term
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Definition
| sex with two of the same sex chromosomes |
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Term
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Definition
| sex with two different sex chromosomes |
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Term
| Which of the sex chromosomes is larger? |
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Definition
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Term
| Describe pseudoautosomal regions of sex chromosomes |
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Definition
| sips of chromosomes that recombine during meiosis |
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Term
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Definition
| transcription factor that controls expression of other genes |
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Term
| Give two examples of X linked recessive diseases |
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Definition
| Ichthymosis (cholesterol not removed from skin cells) and Hemophilia B |
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Term
| Which sex is more effected in X linked dominant inheritance and why? |
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Definition
| Men; only one X chromosome |
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Term
| What is an example of an x linked dominant disease? |
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Definition
| incontinentia pigmenti (melanin penetrates deeper skin layers making swirls), Denotype in males is dominant lethal |
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Term
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Definition
| gene on X that encodes small RNA that covers one X to shut it down |
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Term
| Describe mosaics in females |
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Definition
| patches of cells that either express maternal or paternal X |
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Term
| Epigenetic change alters ____ but not ____ |
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Definition
| phenotype (not true if female is hetero recessive for x linked disease); genotype |
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Term
| What type of disorder is hemophilia A? |
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Definition
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Term
| The carrier of an x linked trait who expresses the phenotype is what? |
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Definition
| manifesting hetero; can only exist in women |
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Term
| Describe genomic imprniting |
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Definition
| epigenetic marks cover gene from either parent and turn it off to balance gene expression; normal |
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Term
| What happens to imprinted regions of genes during meiosis? |
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Definition
| they are erased and reset |
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Term
| Define chromosomal aberrations |
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Definition
| Mutations large enough to be seen on chromosomes via microscope |
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Term
| Describe the effects of chromosomal abnormalities |
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Definition
| Having too much genetic material is better than not having enough; most result in miscarriage |
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Term
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Definition
| field that links chromosomal variations with phenotypes |
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Term
| Describe the physical structure of a chromosome |
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Definition
| centromere (constriction point): where spindle fibers attach during mitosis; long arm (q arm) short arm (p arm) |
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Term
ID region of chromosome:
Euchromatin, lighter staining area, located between centromere and telomere on each arm of chromosome |
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Definition
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Term
ID area of chromosome:
bands of dark regions, heterochromatin |
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Definition
| repetitive non-coding DNA |
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Term
| What are the 3 chromosome shapes seen in humans? |
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Definition
| Acrocentric, Submetacentric (typical shape but shorter at top), and Metacentric (typical shape) |
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Term
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Definition
| Chromosome chart created from amniocentesis, chorionic villus sampling or fetal/DNA sampling; used to observe chromosomal abnormalities |
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Term
| What are 3 uses of a karyotype? |
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Definition
| Confirm diagnosis of Downs, Monitor genetic damage from exposure to toxins, Study evolutionary relationships |
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Term
| Any cell except ___ can be used to examine chromosomes |
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Definition
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Term
| What is the most common chromosomal abnormality detected via amniocentesis? |
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Definition
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Term
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Definition
| Fetal cells and fluid removed to be cultured; performed at 14-16 wks, risk of miscarriage, rec. in women >35 |
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Term
| Describe chorionic villus sampling |
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Definition
| Cells take from chorionic villi; less accurate than amniocentesis, karyotype is made directly from cells; can be done earlier and faster than amnio. |
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Term
| Describe fetal cell/DNA sampling in maternal blood |
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Definition
| fetal cells sorted from maternal cells hen karyotyped; if more mRNA from one parent is present than another, the fetus can have more DNA than expected |
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Term
| Describe screening for trisomy 21 |
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Definition
| ultrasound for structural abnormalities and multiple serum maternal markers for abnormal levels of protein; if risk is detected then diagnostic tests are completed |
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Term
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Definition
| Non Invasive Prenatal testing; requires only maternal blood sample, sensitive, accurate; for high risk patients, cannot detect a large # of defects yet |
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Term
| Describe atypical chromosomes in humans |
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Definition
| When somatic cell chromosome number is not 46, most result in abortion |
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Term
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Definition
| having an extra set of chromosomes; come from fertilization of 1 egg by 2 sperm or when sperm fertilizes diploid egg; lethal |
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Term
|
Definition
| person whose cells has 3 sets of chromosomes |
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Term
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Definition
| missing a single chromosome or having an extra; result of non-disjunction during meiosis, more common in sex chromosomes, effects gene dosage |
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Term
| When children are born with aneupliudy, it is more likely to be ____ than _____ |
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Definition
| trisomy; monosomy (missing one chromosome) |
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Term
| What are the most common forms of autosomal aneuploidies? |
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Definition
| Trisomy 13, 18, and 21; carry fewer genes than others so extra copies are better tolerated |
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Term
| What are the characteristics of someone with trisomy? |
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Definition
| Short, straight sparse hair, atypical creases in hands, loose joints and muscle tone |
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Term
| Describe the down syndrome critical region |
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Definition
| Near end of chr 21; has 3 genes that are assoc with most Downs symptoms |
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Term
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Definition
| Effects aneuploid females (XO); lack bar bodies; not apparent till adolescence when they don't experience puberty; hormones given to stimulate sex structure |
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Term
|
Definition
| XXX; tall with menstrual irregularities; two x's are inactive |
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Term
| Describe klinefelter syndrome |
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Definition
| XXY; long arms/legs, may develop breast tissue, most common cause of male infertility; severely effected men are underdeveloped |
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Term
|
Definition
| XYY; 96% normal, acne with possible speech or reading problems; arise from nondisjunction in sperm |
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Term
| what are the two types of balanced changes to chromosome structure? |
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Definition
| translocations and inversions |
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Term
| Describe unbalanced changes to chromosome structure |
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Definition
| duplications and deletions, can arise de novo, the bigger the change the more severe the phenotype |
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Term
| Describe Copy Number Variants |
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Definition
| Segment of DNA that is at least 1k nucleotides or larger present in variable copy number; many have no known phenotype |
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Term
| Describe comparative genomic hybridization |
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Definition
| Technique that can detect gains or losses of a chromosomal region associated with a phenotype; can pinpoint CNVs assoc. with autism |
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Term
|
Definition
| non homologous chromosomes exchange parts (regions of different chromosomes are swapped); Can lead to improper gene expression if it happens in the middle or a gene |
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Term
| Describe Robertsonian Translocation |
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Definition
| 2 short arms of non homologous chromosomes break off and then the long arms combine into 1 large chromosome |
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Term
| Describe reciprocal translocation |
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Definition
| two different chromosomes exchange parts, less damaging, can be balanced or unbalanced depending on where it occurs |
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Term
|
Definition
| Creates problems during crossing over in meiosis; paracentric doesn't include centromere, pericentric does include centromere |
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Term
| Describe uniparental disomy |
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Definition
| Inheriting 2 homologous chromosomes from one parent and NOT from the other; rare, result of nondisjunction or trisomy |
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Term
|
Definition
| use of living organisms or their products to perform tasks; based on manipulation of DNA |
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Term
| Organisms that harbor DNA from other species are called ____ |
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Definition
| transgenic; each of their cells has the genetic manipulation |
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Term
| Define genetic engineering |
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Definition
| direct manipulation of genes for practical purposes |
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Term
|
Definition
| Green Fluorescent Protein; used to track gene expression |
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Term
| What is the first step of biotechnology? |
|
Definition
| nucleic acid (DNA) extraction |
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Term
| What are the 4 steps of DNA extraction? |
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Definition
| Lysis to release DNA, Digest proteins with enzymes, Separate DNA from proteins and other cellular debris, precipitate DNA with alcohol |
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Term
|
Definition
| polymerase chain reaction; way to amplify/mass produce a certain segment of DNA; lab version of DNA replication in cells |
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Term
| Define amplify in relation to PCR |
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Definition
| making many copies of DNA segment |
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Term
| What is the major advantage of PCR? |
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Definition
| you only need a small amount of DNA to start with |
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Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| What 5 things are needed for PCR? |
|
Definition
| starting DNA sample, Taq, ATCG, 2 short since stranded DNA fragments that serve as primers (complimentary to target sequence at either end); thermal cycler |
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|
Term
| What is the 3 step cycle of PCR? |
|
Definition
| denaturing, annealing and extension |
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Term
|
Definition
| done at high heat to replicate function of helicase; separates DNA |
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|
Term
| Describe annealing in PCR |
|
Definition
| primers bind to complimentary base pairs on target DNA bracketing the target sequence |
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|
Term
| Describe extension in PCR |
|
Definition
| DNA polymerase extends DNA strand in 5'-3' direction attaching the appropriate nucleotides |
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|
Term
| The size of the DNA fragment made in PCR is dependent on what? |
|
Definition
|
|
Term
| Describe restriction enzymes |
|
Definition
| cut at specific restriction enzyme sites to destroy invading DNA; most sites are palindromes (read same front and back) |
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|
Term
| Restriction enzymes and what work together to create recombinant DNA? |
|
Definition
| ligase; seals the DNA strand back up |
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|
Term
| ____ carry DNA from one species to cells of another |
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Definition
|
|
Term
| Donor DNA is usually inserted into a ____ |
|
Definition
| plasmid (closed circular piece of DNA taht exists naturally) |
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|
Term
| Plasmid vectors are taken up by a ____ |
|
Definition
| bacteria; cellular machinery makes protein of interest |
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|
Term
| What are the two categories of use for cloned genes? |
|
Definition
| produce a protein product or prepare many copies of the gene itself |
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Term
|
Definition
| genetically modified organisms; anything that has acquired a gene by artificial means |
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Term
|
Definition
| bacteria or plants with ability to detoxift pollutants |
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|
Term
| How is DNA that has been cut with restriction enzymes recombined? |
|
Definition
| via sticky ends and ligase |
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|
Term
| Describe gene expression profiling |
|
Definition
| uses gene chips or microarrays to detect mRNA in a cell at a given time |
|
|
Term
| How does microarray analysis begin? |
|
Definition
| Isolatig mRNA from a set of cells and making cDNA |
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|
Term
| Describe the color code of microarray genes |
|
Definition
| Red= expressed in CSF from injured tissue; green= expressed in CSF from healthy tissue; Ywllow= expressed in equal amt in injured and healthy tissues; black= genes that are not expressed in either sample |
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|
Term
| What is a significant advantage of microarray expression? |
|
Definition
| can study the action of many genes at once for a big picture of what's going on in the cell at that moment |
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Term
|
Definition
| block expression of specific gene |
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Term
|
Definition
| RNA interference blocks activity of specific mRNA (blocks a specific gene) |
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|
Term
|
Definition
| synthetic DNA molecule 25 nucleotides long; targets specific genes to silence gain of function mutations |
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Term
|
Definition
| Peptide conjugated phosphorodiamidate morpholino oligomer; show promise in treating resistant bacteria |
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Term
|
Definition
| resembled DNA replication; polymerase adds modified nucleotides; once modified nucleotides are included nothing else can be added and the process stops |
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Term
|
Definition
| combination of gene and chromosome |
|
|
Term
| What is the purpose in sequencing a genome? |
|
Definition
| first step to begin to understand function and evolution of an organism |
|
|
Term
| The human genome sequence is a ____ |
|
Definition
| map; of nucleotide sequences |
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|
Term
| What 7 things were essential to lead the HGP? |
|
Definition
| Medndel's laws of inheritance, Determining DNA as inheritance substance, Composition and structure of DNA, discovery of mRNA, producing recombinant DNA, gene cloning, DNA sequencing |
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|
Term
| Who started the early genome sequencing project? |
|
Definition
| Dept of energy in 1987; James Watson from NIH 1989 |
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Term
|
Definition
| one continuous stretch of regions of overlapping sequences generated from the shotgun approach |
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|
Term
| Describe sanger sequencing |
|
Definition
| DNA fragments ordered by size on sequencing gel; laser highlights end base to derive sequence; golden standard method |
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|
Term
| Describe Next Gen Sequencing Technologies |
|
Definition
| business of developing DNA sequence methods; want to develop entire human genome for <$1k |
|
|
Term
T/F:
genes are distributed evenly throughout DNA |
|
Definition
| false; some areas are gene rich or gene poor |
|
|
Term
|
Definition
| non coding DNA found outside of genes; repetitive (transposable elements) and non repetitive (pseudogenes, non coding RNA) |
|
|
Term
ID:
series of repeating units of 2-5 nucleotides |
|
Definition
| short tandem repeat; genetic markers used for DNA fingerprinting |
|
|
Term
| Describe 454 Pyrosequencing |
|
Definition
| fast and affordable way to sequence an entire genome from one person |
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|
Term
| SNPs are mostly ____ regions |
|
Definition
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