Genetic Inheritance & Genetic Crossing

Flashcards based on key vocabulary from lecture notes on genetic inheritance and crossing.

Gametes

The sex cells of an organism (e.g. sperm and egg cells) that merge during fertilization.

Haploid

A cell that contains one complete set of chromosomes (e.g. human gametes contain 23 chromosomes).

Diploid

A cell that contains two complete sets of chromosomes, one from each parent (e.g. somatic cells contain 46 chromosomes).

Fertilization

The fusion of male and female gamete nuclei to form a zygote.

Zygote

The fertilized egg cell that results from the fusion of gametes.

Meiosis

The type of cell division that produces haploid gametes from diploid cells.

Homozygous

An organism with two identical alleles for a specific gene.

Heterozygous

An organism with two different alleles for a specific gene.

Mendelian Genetics

The study of how traits are inherited according to Mendel's laws of inheritance.

Alleles

Different forms of the same gene.

Dominant Allele

An allele that expresses its trait even in the presence of a recessive allele.

Recessive Allele

An allele that expresses its trait only when two copies are present.

Codominance

A situation in which both alleles in a heterozygote are fully expressed.

Incomplete Dominance

A condition in which a heterozygote's phenotype is intermediate between both alleles.

Punnett Square

A diagram that predicts the genotypes of offspring from a genetic cross.

Phenotype

The observable characteristics or traits of an organism, determined by its genotype.

Genotype

The genetic makeup of an organism; the specific alleles present.

Pedigree Chart

A diagram that shows the occurrence of a genetic trait over several generations.

Phenotypic Plasticity

The ability of an organism to change its phenotype in response to environmental conditions.

Chi-squared Test

A statistical method used to determine if there’s a significant difference between expected and observed results.

Linkage

The tendency of genes located close together on a chromosome to be inherited together.

Autosomal Linkage

Linkage of genes located on the non-sex chromosomes.

Sex-linked Traits

Traits that are associated with genes located on the sex chromosomes.

Monohybrid Cross

A cross between individuals focusing on a single trait controlled by one gene.

Dihybrid Cross

A cross between individuals focusing on two traits controlled by two different genes.

Gregor Mendel

The Austrian monk known as the Father of Genetics for his work on pea plant inheritance.

Phenotypic Ratio

The ratio of different phenotypes expressed in offspring.

Genotype Ratio

The ratio of different genotypes that result from a genetic cross.

F1 Generation

The first filial generation of offspring in a genetic cross.

F2 Generation

The second filial generation, resulting from a cross of F1 individuals.

Polygenic Inheritance

A pattern of inheritance in which multiple genes influence a trait.

Continuous Variation

Variation in a trait that falls within a range rather than distinct categories.

Discrete Variation

Variation that falls into distinct categories with no intermediate forms.

Chiasma

The point at which homologous chromosomes exchange genetic material during meiosis.

Segregation

The separation of alleles during gamete formation.

Independent Assortment

The principle that alleles of different genes segregate independently of one another during gamete formation.

Test Cross

A cross between an individual with an unknown genotype and a homozygous recessive individual.

SNP (Single Nucleotide Polymorphism)

A variation in a single nucleotide that occurs at a specific position in the genome.

Polypeptides

Chains of amino acids that make up proteins, coded by genes.

Sexual Reproduction

A type of reproduction that involves the fusion of gametes from two parents.

Amino Acid

The building blocks of proteins, specified by the genetic code.

Gene Therapy

A technique aimed at treating genetic disorders by altering defective genes.

Autosomes

All chromosomes that are not sex chromosomes.

Environmental Influence

Factors in an organism's surroundings that can affect its phenotype.

Parent Generation

The initial generation in a breeding experiment, typically designated as P.

Allelic Frequency

How often an allele appears in a given population.

Mendel's Law of Dominance

The principle that in a heterozygote, one allele may conceal the presence of another.

Mendel's Law of Segregation

The law stating that allele pairs separate during gamete formation.

Autosomal Recessive Disorder

A disorder that occurs when an individual inherits two copies of a recessive allele.

Phenotypic Ratio of a Monohybrid Cross

Typically 3:1 dominant to recessive.

Phenotypic Ratio of a Dihybrid Cross

Typically 9:3:3:1 in a cross with two heterozygous parents.

Blood Type Inheritance

Example of multiple alleles where A, B, and O determine blood type.

SRY Gene

The gene on the Y chromosome that determines male sex characteristics.

Sex Chromosome

Chromosomes that determine the sex of an individual (X or Y chromosomes).

Recombinant Types

Offspring with a new combination of alleles different from the parents.

Scattering of Traits

The varied distribution of characteristics influenced by multiple genes.

Base Pairing

The specific pairing of nucleotides in DNA (A-T and G-C).

Carriers

Individuals who carry one recessive allele for a trait but do not express the associated trait.

Electrophoresis

A technique used to separate DNA fragments based on size.

Dihybrid Cross Example

Involves two traits, for example, coat color and fertility.

Phenotypic Expression

The observable characteristic of an organism resulting from genotype.

Semi-dominance

A form of inheritance where offspring show a mix of traits from both parents.

Genetic Drift

Random changes in allele frequency in a small population.

Frequency of Alleles

A measure of how common an allele is in a population.

Genetic Variation

Diversity in gene frequencies within a population.

Selection Pressure

Environmental factors that favor certain phenotypes over others.

Mitochondrial Inheritance

Genetic transmission of traits determined by genes in the mitochondria, typically maternal.

Health Screenings

Medical tests that look for genetic conditions or diseases.

Antigen

A molecule that can trigger an immune response.

Gene Locus

The specific physical location of a gene on a chromosome.

Trait

A specific characteristic of an organism.

Cloning

The process of creating a genetically identical copy of an organism.

Transgenic Organism

An organism that contains DNA from another species.

Genetic Engineering

Direct manipulation of an organism's genes using biotechnology.

Somatic Cell Therapy

A type of gene therapy that treats genetic disorders in somatic (body) cells.

Specific DNA Sequencing

The process of determining the order of nucleotides in a DNA molecule.

Gene Mapping

Establishing the location of genes on a chromosome.

Cladogenesis

The evolutionary splitting of a parent species into two or more distinct species.

Biodiversity

The variety of life and its processes including the number of species.

Ecosystem Services

The benefits provided by ecosystems to humans.

Environmental Degradation

The deterioration of the environment through depletion of resources.

Mutagen

Any agent that increases the frequency of mutation.

Heritability

The proportion of variation among individuals that can be attributed to genes.

Tetrad

A group of four chromatids formed during meiosis.

Recessive Condition

A condition that does not manifest unless both alleles are recessive.

Ecological Genetics

The study of genetic variation and adaptation in populations.

Necrosis

Tissue death due to disease, injury, or lack of blood flow.

Transcription Factor

A protein that regulates the transcription of genes.

Bioinformatics

The science of collecting and analyzing complex biological data such as genetic codes.

Gene Expression

The process by which information from a gene is used to synthesize a functional gene product.