Mendelian_Genetics_and_Meiosis_revised

Mendel's Laws of Heredity

Principles formulated by Gregor Mendel about how traits are inherited.

Phenotype

The physical appearance of an organism as expressed by its genotype.

Genotype

The genetic makeup of an organism, represented by alleles.

Allele

A form of a gene for a specific trait.

Dominant allele

An allele that is always expressed in the phenotype when present.

Recessive allele

An allele that may not be expressed in the phenotype if a dominant allele is present.

Homozygous

An organism with two identical alleles for a trait.

Heterozygous

An organism with two different alleles for a trait.

Monohybrid Cross

A genetic cross between individuals that differs in only one trait.

F1 Generation

The first generation of offspring obtained from a cross of the parental generation.

F2 Generation

The second generation of offspring, resulting from the self-pollination of the F1 generation.

Law of Segregation

The principle stating that allele pairs separate during gamete formation.

Law of Independent Assortment

The principle that genes for different traits are inherited independently of each other.

Punnett Square

A diagram used to predict the outcome of a genetic cross.

Diploid

A cell that contains two sets of chromosomes (2n).

Haploid

A cell that contains one set of chromosomes (n).

Homologous Chromosomes

Paired chromosomes that have the same genes but may carry different alleles.

Nondisjunction

The failure of homologous chromosomes to separate properly during cell division.

Trisomy

A genetic condition where a gamete with an extra chromosome fuses with a normal gamete.

Monosomy

A genetic condition where a gamete with a missing chromosome fuses with a normal gamete.

Polyploidy

A condition where an organism has more than two complete sets of chromosomes.

Pedigree

A diagram that shows the genetic history of a family.

Recessive Heredity

A genetic trait requiring two copies of the allele to be expressed.

Dominant Heredity

A genetic trait that only requires one copy of the allele to be expressed.

Incomplete Dominance

A genetic scenario where the dominant allele is only partially expressed.

Codominance

A genetic scenario where both alleles are fully expressed in the phenotype.

Multiple Alleles

The presence of more than two alleles for a genetic trait within a population.

Sex-linked Traits

Traits controlled by genes located on sex chromosomes.

Polygenic Inheritance

A trait controlled by two or more genes, leading to a range of phenotypes.

Gene Linkage

The tendency of genes located on the same chromosome to be inherited together.

Environmental Influences

External or internal factors that can affect gene expression and phenotype.

Karyotype

A visual representation of all chromosomes in a cell used for comparison.

Amniocentesis

A medical procedure used to obtain amniotic fluid for genetic testing.

Genetic Screening

A method to test individuals for genetic disorders.