Genetics Flashcards
Gregor Mendel
Definition:
A scientist who is known as the father of genetics.
Example:
Gregor Mendel experimented on pea plants.
Trait
Definition:
A genetically determined characteristic.
Example:
Every person is born with different traits.
Alleles
Definition:
An alternative form of a gene that is located at a specific position on a specific chromosome.
Example:
Alleles can be dominant or recessive.
Genotype
Definition:
The genetic constitution of an individual organism.
Example:
Genotypes are represented by letters.
Phenotype
Definition:
The set of observable characteristics of an individual.
Example:
Brown eyes, green eyes, and blue eyes are examples of Phenotypes.
Gene
Definition:
A unit of heredity that is transferred from a parent to offspring and is held to determine some characteristics of the offspring.
Example:
We get different genes from our parents.
Gamete
Definition:
A mature haploid male or female germ cell that is able to unite with another of the opposite sex in sexual reproduction to form a zygote.
Example:
If you are a female, your gamete is an egg.
Pedigree
Definition:
The record of descent of an animal, showing it to be purebred.
Example:
An animal that is a Pedigree is valued more than mixed breeds.
Heterozygous
Definition:
When an organism’s cells contain two different alleles of a gene.
Example:
When a gene is heterozygous, the genotype is represented by a small letter and a big letter.
Homozygous
Definition:
When an individual has two of the same allele.
Example:
An allele can be homozygous dominant or homozygous recessive.
Dominant Allele
Definition:
The gene that masks or hides the presence of the other allele for a given trait.
Example:
A dominant allele will show up more likely than a recessive allele.
Recessive Allele
Definition:
An allele that produces its characteristic phenotype only when its paired allele is identical.
Example:
A recessive allele is represented by two small letters in a genotype.
Law of Independent Assortment
Definition:
The principle, originated by Gregor Mendel, stating that when two or more characteristics are inherited, individual hereditary factors assort independently during gamete production.
Example:
In the Law of Independent Assortment, the alleles segregate into gametes seperately.
The Law of Segregation
Definition:
The law of inheritance that states that the two alleles of each gene get seperated and only one allele from each parent will be passed to the offspring.
Example:
The Law of Segregation was come up with by Gregor Mendel.
Punnett Square
Definition:
A diagram that is used to predict an outcome of a particular cross or breeding experiment.
Example:
A Punnett Square can give you a good estimate of what the offspring will look like.
Autosomes
Definition:
Any chromosome that is not a sex chromosome.
Example:
Humans have 22 pairs of autosomes.
Sex Chromosomes
Definition:
A chromosome involved with determining the sex of an organism.
Example:
Humans have 1 pair of sex chromosomes.
Homologous Chromosomes
Definition:
Chromosome pairs that are inherited from each parent.
Example:
The two homologous chromosomes form an homologous pair.
Incomplete Dominance
Definition:
A genetic situation in which one allele does not completely dominate another allele, and therefore results in a new phenotype.
Example:
A pink flower is an example of incomplete dominace.
Diploid
Definition:
Containing two complete sets of chromosomes, one from each parent.
Example:
The number of diploid cells in humans is 46.
Haploid
Definition:
Having a single set of unpaired chromosomes.
Example:
Gametes are haploid cells.
Genome
Definition:
The haploid set of chromosomes in a gamete or microorganism, or in each cell of a multicellular organism.
Example:
Each genome contains all of the information needed to build and maintain that organism.
Genetics
Definition:
The genetic properties or features of an organism, characteristic, etc.
Example:
Genetics is concerned with heredity and how particular qualities or traits are passed on from parents to offspring.
Carrier
Definition:
A person or other organism that possesses a particular gene so that the associated characteristic (such as a hereditary disease) is not displayed but may be passed to offspring.
Example:
A carrier is not affected but has a chance of producing offspring with that disease.
Hybrid
Definition:
The offspring of two plants or animals of different species or varieties.
Example:
An example of a hybrid would be a donkey.
Purebred
Definition:
An animal bred from parents of the same breed or variety.
Example:
A purebred is homozygous.
Monohybrid Cross
Definition:
A mating between individuals who have different alleles at one genetic locus of interest.
Example:
Either phenotypes could surface in a monohybrid cross.
Dihybrid Cross
Definition:
A cross between first-generation offspring of two individuals that differ in two traits of particular interest.
Example:
Mendel invented the dihybrid cross.
Parents
Definition:
An organism from which younger ones are derived.
Example:
Everyone’s parents gave them their traits.
Offspring
Definition:
The product of reproduction of a new organism produced by one or more parents.
Example:
Everyone’s offspring shares traits with them.
F1
Definition:
The original cross between two parent species.
Example:
F1 leads to F2.
F2
Definition:
The cross between 2 members of the F1 generation.
Example:
The F2 generation varies greatly.
Sex Linkage
Definition:
The phenotypic expression of an allele that is dependent on the gender of the individual and is directly tied to the sex chromosomes.
Example:
Haemophillia is a sex-linked recessive allele that is only present on the X chromosome.
X Linked
Definition:
The gene causing the trait or the disorder is located on the X chromosome.
Example:
Carrier females who have only one copy of the mutation do not usually express the x-linked phenotype.
