SCT III Flashcards
(46 cards)
Comparative genomics
The field of science that studies the similarities between the genome structure and function of different species.
Pseudogene
Shows a high degree of sequence homology to a non-allelic functional gene, but which is itself nonfunctional.
i.e. a section of DNA that is similar to a functional gene, but it does not produce a functional protein.
Hominins
Extinct species that are more closely related to humans than other great apes.
Ideogram
A schematic representation of chromosomes; a standardized, species-specific set of chromosomes with G-banding used to show the relative size of the chromosomes and their characteristic banding patterns.
Karyotype
Is an individual’s collection of chromosomes.
It describes the number, appearance, and physical characteristics of chromosomes in the nucleus of a cell in an individual organism.
A verbal description with symbols and abbreviations.
Karoygram
A micro-photograph of all chromosomes of a single cell represented in a standard format.
Chromosomes are sorted and re-arranged in pairs by their size and position of their centromeres.
I.e. it is a photograph of the whole set of all 22 identical chromosome pairs plus the 2 gender specific chromosomes (XX/XY)
Chimera
An organism derived from more than one zygote.
Trisomy rescue
In a nonviable trisomic embryo, chance of loss of one of the trisomic chromsomes by anaphase lag, producing a disomic cell that can eventually form a viable embryo.
A cause of uniparental disomy (UPD). UPD may case:
- Rare Mandelian diseases
- Angelman syndrome
- Prader-Willi syndrome
Allelic heterogeneity
Existence of many different mutations but all within the same gene in unrelated people with the same phenotype
Anticipation
Tendency for the severity of a condition to increase in successive generations
Commonly due to bias of ascertainment but seen for real with dynamic mutations
Coding RNA
Messenger RNA that codes for a protein
Common variant
Conventionally, a variant whose frequency is >0.05.
Conserved sequence
A sequence (of DNA or sometimes protein) that is identical or recognizably similar across a range of organisms
Dominant negative effect
Situation where a mutant protein interferes with the function of its normal counterpart in a heterozygous person
Dynamic mutation
An unstable expanded repeat that changes size between parent and child
Exome
Totality of exons in a genome
Exon junction complex
A set of proteins that are bound to mRNAs during splicing, at the positions where introns have been removed
Founder effect
High frequency of a particular allele in a population because the population is derived from a small number of founders, one or more of whom carried that allele
Frame-shift mutation
A mutation that alters the triplet reading frame of a mRNA (by inserting or deleting a number of nucleotides that is not a multiple of 3)
Gain-of-function mutations
Mutations that cause the gene product to do something abnormal, rather than simply to lose function.
Usually the gain is a change in the timing or level of expression
Genotype-phenotype correlation
Extent to which a phenotype can be predicted from a genotype.
Typically poor in humans, better in experimental animals which are inbred and live under standard lab conditions
Haploinsufficiency
A locus shows haploinsufficiency if producing a normal phenotype requires more gene product than the amount produced by a single functional allele
Heteroplasmy
Mosaicism, usually within a single cell, for mitochondrial DNA variants
Homoplasmy
Of a cell or organism, having all copies of the mitochondria DNA identical
