Terminology Flashcards
What is complex heterozygote (aka genetic compound)?
An individual who has two different mutated alleles, one on each chromosome of the homologue pair
What is genomic imprinting?
The non-equvialent expression of genes, which is based on parent-of-origin (the Imprinted gene is Inactivated)
Define PCR
Enzymatic amplification of a fragment of DNA between a pair of primers
What is uniparental disomy (UPD)?
A case in which an offspring receives 2 copies of a chromosome from 1 parent and no copies from the other parent
What is genomics?
The study of the structure, function and interaction of the genome
What does dominant mean?
The trait is expressed even in heterozygote (one allele is enough for expression)
What is locus heterogeneity?
Mutation in many different loci (i.e., different genes) produce the same phenotype
What is heterozygote advantage?
A mechanism by which a recessive allele, though harmful in the homozygous condition, is maintained in a population because it provides some adaptive advantage in heterozygotes
What is driver mutation?
A mutation which confers a selective growth advantage
What is gene?
Unit of inheritance
Define sex-influenced characteristics
The phenotype is determined by autosomal genes that are readily more expressed in one of the sexes (there is a higher penetrance in one sex)
Define sex-limited characteristics
The phenotype is determined by autosomal genes whose expression is limited to only one of the sexes (due to hormones or enzymes in one of the sexes)
What is mutation?
Heritable and permanent changes in the DNA seqeunce
What does incomplete penetrance mean?
Although the individual carry the genotype, the phenotype is not expressed (P < 100%)
Define restriction endonuclease (enzymes)
An enzymes that recognized specific double-strand DNA sequence (recognition site) and cleave at or near the site
What is wild allele?
The most frequent allele in the population
What is penetrance?
The probability of a genotype that it will manifest the trait (i.e., the phenotype)
What is chimerism?
An individual composed of cells derived from two genetically different zygotes
What is epigenetics?
A heritable mechanisms which affect the transcriptional state of a gene without changing the DNA sequence
What is epistasis?
The interaction of two different genes that affect the same phenotype (usually describe the supression of one gene on the other)
What is morphogene?
A soluble signaling molecule that has a role in the developing egg or embryo, depending on its concentration gradient
What is haploid insufficiency?
A genetic cause in which the contribution of the normal allele is not enough to prevent the disease, because of loss-of-function mutation at the other allele
What is allele?
Different variations of the same gene
What is passenger mutation?
A mutation which does not affect the fitness of the tumor
What is probe?
A cloned DNA or RNA fragment, labeled with fluoroscensce or another detectable tracer, used to identify its complementary sequences by molecular hybridization
Define linkage disequilibrium (LD)
The non-random association of alleles at two or more loci that may or may not be on the same chromosome
What is genome?
The total hereditary information
Define gel electrophoresis
Separation of DNA, RNA or proteins by size (molecular weight)
What is ploidy?
The number of sets of chromosomes in a cell
What is variable expression (aka expressivity)?
The extent at which the genetic defect is expressed
What is mosaicism?
An individual or a tissue having two cell lines differing in the genotype, derived from a single zygote
What does recessive mean?
The trait is expressed in homozygote (two alleles are required for expression)
What is allele heterogeneity?
Different mutation in the locus (i.e., different alleles of the same gene) produce the same phenotype
What is polymorphism?
DNA variation with known population frequency
What is locus?
The position of a gene on the chromosome
What is multiple allelism?
A gene may have more than 2 alleles in the population
What is pleiotropy?
One gene which has multiple phenotypes
What is phenotype?
A visible trait
