Genetics Flashcards
what is karyotype
display of individuals set of chromosomes, arranged in numerical order
what is karyotype used for
identifying large abnormalities in chromosome structure or number (trisomy 21)
what is genotype
compostion of genes, carries genetic information, expressed in alleles (BB, Bb, bb) or actual DNA sequence
what is phenotype
observable traits/the way a gene is expressed (high, eye colour)
what is an autosome
chromosome that is the same in males an females
what is an autosomal dominant gene
affected gene is dominant over non affected - if heterozygous, affected allele will produce phenotype
what is autosomal recessive gene
affected gene is recessive, if heterozygous person is carrier but unaffected
what is x-linked inheritance
x chromosome gene isn’t working properly, more commonly affects males as they only have one x chromosome
what is polygenic inheritance
traits in variation caused by combined effects of multiple genes
what is multifactorial inheritance`
environmental factors cause variation in the trait, influenced by genes as well as stress/exercise etc
what is aneuploidy
a condition where a person has an additional or missing chromosomes
what is non-disjunction
failure of chromosomes to separate properly during meiosis or mitosis, resulting in daughter cells with an abnormal number of chromosomes
what is turner syndrome
sex chromosome aneuploidy - X
characteristics: short, infertal, congenital abnormalities (cardiac/renal), normal intelligence
what is klinefelter syndrom
sex chromosome aneuploidy - XXY
characteristics: tall, gynecomastia, hypogonadism, infertility, learning difficulties
what is XYY
sex chromosome aneuploidy, learning difficulties, no dysmorphic features, normal fertility, behaviour issues (ADD, hyperactivity, impulsiveness)
what are examples of chomosome anomalies
deletion/dupications: large pieces of extra or missing chromosomal material
translocations/inversions: misplaced pieces of chromosome material
what is the process from DNA to mRNA
transcription
what is the process from mRNA to protein
translation
what are examples of autosomal dominant genetic diseases
achondroplasia, marfan syndrom, huntington’s disease, hypertropick cardiomyopathy, hereditary breast/ovarian cancer
what are examples of autosomal recessive genetic diseases
cystic fibrosis, sickle cell anemia, tay sachs disease, phenylkenonuria (PKU), heretidary hemochromatosis
what are x -linked genetic diseases
duchenne muscular dystrophy, fabry disease, hemophilia, fragile x syndrome, x-linked adrenoleukodystrophy
what is variable expressivity
not all family members affected by a genetic disease will have the same signs & symptoms or course of disease
what is incomplete penetrance
not all gene carriers will have the disease - ex) BRCA gene mutation means you are at higher risk of getting cancer, but not everybody with that gene gets cancer.
A gene that clinically manifests in everybody is 100% penetrant (although it still may have variable expressivity)
what is fluorescence in situ hybridization (FISH) useful for
detecting submicroscopic deletions/duplications or aneuploidy
what is karyotyping useful for
large chromosome deletions/duplications, chromosome rearrangements (translocations) or aneuploidy (trisomy)
what is chromosomal microarray useful for
the smallest submicroscopic deletions/duplications, aneuploidy
what is molecular genetic testing and what is it used for
it is the analysis of human DNA, down to the individual base units, andis used to detect heritable disease-related gene mutations for clinical purposes
