Genetics words

Barr body	A condensed, inactive X chromosome found in the nuclei of female mammals.
Chromosome	A structure made up of DNA and proteins that carries genetic information in the form of genes.
Coding region	The part of a gene that contains the instructions for making a functional protein.
Codon	A sequence of three nucleotides in DNA or RNA that codes for a specific amino acid or stop signal during protein synthesis.
Dominant	A trait or allele that is expressed when paired with a recessive allele.
Electroporation	A technique that uses an electric field to introduce DNA or other molecules into cells.
Exon	The coding regions of a gene that are transcribed into mRNA and then translated into protein.
Frameshift	A type of mutation that occurs when the addition or deletion of nucleotides in a gene changes the reading frame of the codons, resulting in a non-functional protein.
Gamete	A mature haploid cell, either an egg or a sperm, that can combine with another gamete during fertilization to form a zygote.
Gene	The basic physical and functional unit of heredity, made up of DNA.
Haploid	Having a single set of chromosomes, as in gametes.
Haploploidy	A type of sex determination in which males have a single set of chromosomes and females have two sets.
Helicase	An enzyme that unwinds double-stranded DNA during replication or transcription.
Heterochromatin	A tightly packed form of chromatin that is inaccessible to the transcriptional machinery, typically found in regions of the genome that are not actively transcribed.
Histone	A protein that helps organize and package DNA in the nucleus of eukaryotic cells.
Independent assortment	The random distribution of homologous chromosomes during meiosis, resulting in the production of genetically diverse gametes.
Intron	The non-coding regions of a gene that are transcribed into mRNA but are spliced out before translation.
Karyotype	The complete set of chromosomes in an individual, arranged in pairs according to size, shape, and other characteristics.
Ligase	An enzyme that catalyzes the formation of covalent bonds between adjacent nucleotides in DNA or RNA.
Ligation	The process of joining two nucleic acid fragments using a ligase enzyme.
Mean	The average value of a set of data, calculated by dividing the sum of the values by the total number of values.
Meiosis	The process of cell division that produces haploid gametes from diploid cells, involving two rounds of division and resulting in the shuffling of genetic information.
Mendelian trait	A trait that follows the principles of Mendelian inheritance, such as the inheritance of dominant and recessive alleles.
Mitosis	The process of cell division that produces two genetically identical daughter cells from a single parent cell, involving one round of division.
Non-coding region	The part of a gene that does not contain the instructions for making a functional protein.
Nucleoside	A molecule composed of a nitrogenous base (adenine, guanine, cytosine, thymine, or uracil) and a sugar (ribose or deoxyribose) that forms the building blocks of nucleic acids.
Nucleotide	A molecule composed of a nucleoside and a phosphate group that is the basic unit of nucleic acids.
Oocyte	A female gamete (egg cell).
Phases of cell cycle	The series of events that a cell undergoes as it grows and divides, including interphase (G1, S, and G2 phases) and mitotic phase (prophase, prometaphase, metaphase
Phases of meiosis	The series of events that occur during meiosis, including prophase I, metaphase I, anaphase I, telophase I, cytokinesis, prophase II, metaphase II, anaphase II, telophase II, and cytokinesis II.
Phases of mitosis	The series of events that occur during mitosis, including prophase, prometaphase, metaphase, anaphase, telophase, and cytokinesis.
Polar body	A small, non-functional cell that is produced during oogenesis, containing little cytoplasm and DNA, and eventually degenerates.
Recessive	A trait or allele that is only expressed when paired with another recessive allele.
Recombinant	An individual or cell that contains a combination of alleles from both parents due to recombination during meiosis or genetic engineering techniques.
Segregation of alleles	The separation of homologous chromosomes during meiosis, resulting in the distribution of alleles into different gametes.
Sex chromosome	A chromosome that determines the sex of an individual, typically the X or Y chromosome in mammals.
Standard deviation	A measure of the amount of variation or dispersion in a set of data, calculated by taking the square root of the variance.
Telomerase	An enzyme that adds repetitive nucleotide sequences to the ends of linear chromosomes, called telomeres, to prevent them from shortening during replication.
Telomere	The repetitive nucleotide sequence at the ends of linear chromosomes, which protects the genetic information from degradation during replication and prevents fusion with other chromosomes.
Thymine dimer	A type of DNA damage that occurs when two adjacent thymine bases on the same strand of DNA become covalently bonded to each other, typically caused by exposure to UV radiation.
Trait	A characteristic or feature of an organism that is determined by its genetic makeup and/or environmental factors.

Acrocentric	A type of chromosome in which the centromere is located near one end, resulting in a long arm and a short arm.
Allele	One of two or more alternative forms of a gene that arise by mutation and are found at the same locus on a chromosome.
Autosome	A chromosome that is not a sex chromosome and is present in the same number and type in males and females.
Base substitution	A type of mutation that involves the replacement of one nucleotide with another.
Biallelic	A genetic locus or trait that has two possible alleles.
Centromere	The region of a chromosome that holds the two sister chromatids together during cell division and to which the spindle fibers attach.
Chromatid	One of two identical halves of a replicated chromosome, joined at the centromere.
Chromosomal sex determination	The process by which an organism's sex is determined by the presence or absence of certain chromosomes, such as the X and Y chromosomes in mammals.
Codominance	A form of inheritance in which both alleles contribute to the phenotype of the heterozygote.
Cohesin	A protein complex that holds sister chromatids together during cell division until they are separated during anaphase.
Continuous trait	A trait that shows a continuous range of variation rather than distinct categories.
Contraction of an STR	A type of mutation in which the number of repeats in a short tandem repeat (STR) region of DNA is reduced.
CoT curve in eukaryotes and the three steps	A plot of the reassociation kinetics of denatured DNA fragments as a function of the Cot value (product of concentration and time) in eukaryotes. The three steps are: single-stranded DNA (Cot 0.01-0.1), intermediate reassociation (Cot 0.1-10), and highly repetitive DNA (Cot > 10).
Deletion	A type of mutation in which a segment of DNA is lost or deleted from a chromosome.
Dihybrid	A genetic cross between individuals that differ in two traits or at two genetic loci.
Dihybrid cross	A type of genetic cross involving two traits or two genetic loci.
Dioecious	Having separate sexes, with male and female reproductive structures on separate individuals.
Diploid	Having two sets of chromosomes, one inherited from each parent.
Discontinuous trait	A trait that shows distinct categories rather than a continuous range of variation.
Discrete trait	A trait that is determined by a single gene or a small number of genes and shows distinct categories rather than a continuous range of variation.
Dosage compensation	The mechanism by which organisms equalize the expression of X-linked genes between males and females, often by inactivating one of the two X chromosomes in females.
Environmental sex determination	The process by which an organism's sex is determined by environmental factors rather than genetic factors, such as temperature or social cues.
Expansion of an STR	A type of mutation in which the number of repeats in a short tandem repeat (STR) region of DNA is increased.
Forward mutation	A type of mutation that alters the wild-type phenotype or genotype.
Four major sources of mutation	The four main causes of genetic mutations are errors during DNA replication, exposure to mutagens, errors during DNA repair, and recombination.
Gain-of-function mutation	A type of mutation that enhances the normal function of a protein or confers a new function.
Gene dosage sex determination	The process by which an organism's sex is determined by the number of copies of a particular gene or set of genes, such as the number of X chromosomes in some insects.
Genetic/genic sex determination	The sex of an organism is determined by its genotype.
Genic balance sex determination	The sex of an organism is determined by the ratio of X chromosomes to autosomes.
Genetic sex determination	The sex of an organism is determined by the presence or absence of specific sex chromosomes.
Germline mutation	A mutation that occurs in the cells that give rise to gametes (sperm or eggs).
Hemizygous	A condition where only one allele is present for a particular gene in an individual.
Hermaphroditic	An organism that has both male and female reproductive organs.
Heterogametic	The sex with two different sex chromosomes (e.g., XY in mammals).
Heterozygote	An individual that has two different alleles for a particular gene.
Homogametic	The sex with two identical sex chromosomes (e.g., XX in mammals).
Homozygote	An individual that has two identical alleles for a particular gene.
Incomplete dominance	A type of inheritance where the phenotype of the heterozygote is intermediate between the phenotypes of the homozygotes.
Indel	A type of mutation that involves the insertion or deletion of one or more nucleotides in a DNA sequence.
In-frame insertion or deletion	A type of indel where the number of inserted or deleted nucleotides is a multiple of three, so that the reading frame of the gene is not disrupted.
Insertion	A type of mutation that involves the insertion of one or more nucleotides in a DNA sequence.
Intergenic suppressor mutation	A type of mutation that occurs in a different gene from the original mutation, but suppresses its effect.
Intragenic suppressor mutation	A type of mutation that occurs within the same gene as the original mutation, but suppresses its effect.
Kinetochore	A protein structure on chromosomes that attaches to microtubules and pulls the chromosomes apart during cell division.
Klinefelter Syndrome	A genetic disorder in males where there is an extra X chromosome (XXY).
Lagging strand	The strand of DNA that is synthesized in short, discontinuous fragments during DNA replication.
Leading strand	The strand of DNA that is synthesized continuously during DNA replication.
Lethal mutation	A mutation that causes the death of an organism or its offspring.
Loss-of-function mutation	A type of mutation that causes a gene to lose its normal function.
Meristic characteristic	A type of trait that can be counted, such as the number of vertebrae in an organism.
Metacentric	A type of chromosome where the centromere is located near the middle.
Missense mutation	A type of mutation that changes one amino acid in a protein.
Model organisms: common and scientific names	Organisms that are used in scientific research because they are easy to manipulate and have characteristics that are similar to those of other organisms.
Molecular genetics	The study of the structure and function of genes at the molecular level.
Monoecious	An organism that has separate male and female reproductive structures on the same individual.
Neutral mutation	A type of mutation that does not affect the function of the gene or organism.
Nonsense mutation	A type of mutation that creates a premature stop codon in a protein-coding gene.
Okazaki fragment	A short DNA fragment that is synthesized on the lagging strand during DNA replication.
Phenotype	The observable traits of an organism, which are determined by its genotype and environment.
Polygenic inheritance	A type of inheritance where a trait is controlled by multiple genes.
pseudoautosomal	Region of homology between X and Y chromosomes that undergoes pairing and recombination during meiosis
QTL	Quantitative Trait Locus
qualitative trait	A trait that can be categorized into distinct phenotypic classes, such as flower color or blood type
quantitative trait	A trait that exhibits continuous variation and can be measured, such as height or weight
reverse mutation	A mutation that restores the original wild-type DNA sequence and phenotype from a mutant allele
sequential hermaphroditism	A type of hermaphroditism where an individual changes sex during their lifetime, either once or multiple times
short tandem repeat polymorphism	A type of genetic variation where a short sequence of DNA is repeated a variable number of times
shugoshin	A protein that protects centromeric cohesin from being degraded during meiosis I, ensuring proper chromosome segregation
silent mutation	A mutation that does not change the amino acid sequence of a protein due to the degeneracy of the genetic code
single nucleotide polymorphism	A type of genetic variation where a single nucleotide differs between individuals in a population
slippage	A mechanism of DNA replication or repair where the DNA polymerase or other proteins slip or slide on the DNA template, leading to the addition or deletion of one or more nucleotides
somatic mutation	A mutation that occurs in a somatic cell and is not passed on to offspring
SRY	Sex-determining Region Y
submetacentric	A type of chromosome that has the centromere slightly off-center, resulting in two unequal arms of different lengths
suppressor mutation	A mutation that restores the normal phenotype of a mutant or defective allele, often by compensating for the loss or gain of function of the original gene product
tautomers	Isomers of nucleotides or nucleic acids that differ in the position of protons and electrons, leading to base-pairing errors and mutations during DNA replication or repair
telocentric	A type of chromosome that has the centromere at one end, resulting in only one arm of the chromosome
transcription factor binding site	A specific DNA sequence that is recognized and bound by a transcription factor, enabling the regulation of gene expression and protein synthesis
transition	A type of base substitution mutation where a purine nucleotide (A or G) is replaced by another purine, or a pyrimidine nucleotide (C or T) is replaced by another pyrimidine
transmission genetics	The study of how genetic traits are passed from parents to offspring, including the principles of segregation, independent assortment, and dominance/recessiveness
transversion	A type of base substitution mutation where a purine nucleotide is replaced by a pyrimidine, or vice versa
Turner Syndrome	A genetic disorder that affects females and is caused by the complete or partial absence of one X chromosome, leading to short stature, infertility, and other health problems
variable number tandem repeat	a location in a genome where a short nucleotide sequence is organized as a tandem repeat. These can be found on many chromosomes, and often show variations in length (number of repeats) among individuals.

ascospore	a haploid spore produced within the ascus (sac) of fungi such as yeasts and molds.
auxotrophs	mutant strains of organisms that require specific nutrients to grow, which the parent strain can produce on its own.
backcross	the mating of a hybrid organism with one of its parental types.
cis	a configuration in which two alleles of a gene are located on the same chromosome.
competent cells	bacterial cells that can take up and incorporate foreign DNA from their environment.
conjugation	a process of bacterial genetic exchange in which genetic material is transferred from one cell to another through direct physical contact.
coupling	a configuration in which a chromosome carries two dominant or two recessive alleles of two different genes on the same homolog.
episome	a genetic element that can replicate either as an independent plasmid or as part of a chromosome.
F-factor	a plasmid found in certain strains of E. coli that is responsible for the transfer of genetic material during conjugation.
Hfr	a bacterial strain that carries the F-factor plasmid integrated into its chromosome.
IS2	a mobile genetic element in bacteria that can cause insertional mutations.
IS3	a type of transposable element in bacteria that can cause insertional mutations.
linkage	the tendency of genes to be inherited together because they are located close to each other on the same chromosome.
linkage disequilibrium	a non-random association of alleles at different loci in a population.
linked	genes that are located near each other on the same chromosome and tend to be inherited together.
locus/loci	a specific location on a chromosome where a gene is located.
minimal media and primary components	a defined culture medium containing the minimal nutrients required for growth of a specific microorganism.
nonrecombinant	progeny that carry the same allele combination as one of the parental strains.
oriT	a site on a plasmid or chromosome where DNA replication is initiated.
oriV	a site on a plasmid or chromosome where DNA replication is initiated.
phase	the relationship between alleles of two genes on homologous chromosomes.
pilin	a protein that makes up the hair-like pili on the surface of bacterial cells.
pilus	a hair-like appendage on the surface of bacterial cells that is involved in conjugation.
plasmid	a small, circular DNA molecule that can replicate independently of the chromosome.
prototrophs	wild-type strains of organisms that can synthesize all the nutrients they need for growth.
recombination fraction	the proportion of recombinant offspring in a genetic cross.
repulsion	a configuration in which two alleles of a gene are located on different homologous chromosomes.
sonication	a method of breaking open cells using high-frequency sound waves.
tra genes	a set of genes on the F-factor plasmid that are involved in the transfer of genetic material during conjugation.
trans	a configuration in which two alleles of a gene are located on different chromosomes.
transduction	the transfer of genetic material from one bacterial cell to another by a virus.
transformation	the uptake and incorporation of free DNA from the environment by bacterial cells.

asymptomatic carrier	an individual who has an infectious disease but does not show any symptoms of the disease
bimodal distribution	a probability distribution that has two different modes
centiMorgan	a unit of measurement for genetic linkage or recombination between genes on a chromosome
chromosome maps	visual representations of the relative locations of genes and other important features on a chromosome
concordant	a term used to describe a pair of individuals who both exhibit a particular trait or characteristic
consanguinity	the mating of individuals who are closely related, such as first cousins or siblings
deletion mapping	a technique used to determine the location of a gene on a chromosome by analyzing the phenotypic effects of different-sized deletions that include or exclude the gene
discordant	a term used to describe a pair of individuals in which only one individual exhibits a particular trait or characteristic
dizygotic twins	twins that develop from two separate eggs and sperm, also known as fraternal twins
excluded	a term used to describe a linkage analysis result in which a particular genetic marker is not linked to a disease gene
FISH	a molecular biology technique that uses fluorescent probes to visualize specific DNA or RNA sequences in cells or tissues, Fluorescent in-situ hybridization
fixed allele	an allele that is present in all members of a population and is not subject to change or evolution
Fluorescent In Situ Hybridization	a molecular biology technique that uses fluorescent probes to visualize specific DNA or RNA sequences in cells or tissues
genetic drift	random fluctuations in the frequency of alleles in a population due to chance events
Hardy-Weinberg Equilibrium	a mathematical model that predicts the frequencies of alleles and genotypes in a population under certain conditions of random mating and no selection
heterokaryon	a cell or organism that contains two or more genetically different nuclei or genomes
linkage mapping	A genetic map showing the relative positions of genetic markers along a chromosome that is determined by the recombination frequency
LOD	log of odds - a statistical measure of the strength of linkage between two genetic markers or a marker and a disease gene
lost allele	an allele that becomes extinct in a population due to genetic drift or selection
map unit	a unit of measurement for genetic linkage or recombination between genes on a chromosome, equivalent to 1% recombination
monozygotic twins	twins that develop from a single fertilized egg and are genetically identical, also known as identical twins
negative correlation	a statistical relationship in which two variables tend to change in opposite directions
Neutral theory	a theory of molecular evolution that proposes that most genetic variation within populations is neutral or selectively neutral
non-random mating	a violation of the assumption of random mating in population genetics models, in which individuals are more likely to mate with certain types of individuals than with others
obligate carrier	an individual who carries a disease-causing allele but does not exhibit any symptoms of the disease
pedigree symbols	graphical symbols used to represent family relationships and genetic information in a pedigree
physical maps	visual representations of the physical distances between genes and other important features on a chromosome
population	a group of interbreeding individuals of the same species occupying a defined geographic area
population genetics	the study of the genetic makeup of populations and how genetic variation changes over time
positive correlation	a statistical relationship in which two variables tend to change in the same direction
probability of allele fixation	the probability that a particular allele will become fixed or go to fixation in a population, meaning that it will be the only allele present at that locus in all individuals
proband	the first individual in a family to be diagnosed with a particular disease or condition
random genetic drift	the random fluctuations in allele frequencies in a population due to chance events
random mating	mating between individuals where the choice of partner is not influenced by their genotype or phenotype
random union of gametes	the chance fusion of male and female gametes during sexual reproduction
skewed distribution	a distribution in which the frequency of observations is not symmetrical around the mean
somatic cell hybridization	the fusion of somatic cells from different individuals or species to create hybrid cells
subpopulation	a group of individuals within a larger population that share a common characteristic
suggestive	a statistical result that is not statistically significant, but may still indicate the presence of an effect
Theory of Selective Neutrality	the hypothesis that most genetic variation within populations is selectively neutral and does not affect fitness
three-point test cross	a genetic cross used to determine the order and distance between three linked genes
two-point test cross	a genetic cross used to determine the genetic linkage between two genes
unfixed allele	an allele that has not yet reached fixation in a population
whole chromosome painting	a technique used to label and identify entire chromosomes or chromosome segments using fluorescent probes

complementation	A phenomenon in which two different mutations complement each other to produce a wild-type phenotype.
dominant epistasis	A type of gene interaction where a dominant allele of one gene masks the expression of another gene.
double recessive epistasis	A type of gene interaction where the expression of a trait is dependent on the presence of two recessive alleles in two different genes.
epistasis	A phenomenon where the expression of one gene is dependent on the presence of one or more modifier genes.
equilibrium average homozygosity	The proportion of homozygous individuals expected in a population that is in Hardy-Weinberg equilibrium.
expressivity	The degree to which a genetic trait is expressed in an individual.
genetic heterogeneity	The phenomenon where different genetic mutations can lead to the same phenotype.
incomplete penetrance	The phenomenon where not all individuals with a particular genotype exhibit the expected phenotype.
intercross	A cross between two individuals who are both heterozygous for the same two genes.
Lyons hypothesis	A hypothesis that proposes that X chromosome inactivation occurs randomly and independently in each cell during early development.
penetrance	The proportion of individuals with a particular genotype who exhibit the expected phenotype.
phenocopy	A non-genetic trait that is similar to a genetic trait and is caused by environmental factors.
pleiotropy	The phenomenon where a single gene can have multiple effects on an individual's phenotype.
polydactyly	A genetic trait characterized by the presence of extra fingers or toes.
recessive epistasis	A type of gene interaction where the expression of a trait is dependent on the presence of two recessive alleles in the same gene.