Bio chap 12: Mendelian Genetics Lecture Notes

These flashcards cover key vocabulary and concepts related to Mendelian Genetics, as discussed in the lecture notes.

Alleles

Different versions of the same gene.

Character

A heritable feature, like flower color.

Trait

A variant of a character, like white or purple flowers.

Phenotype

The physical appearance of an organism.

Genotype

The genetic makeup of an organism.

Locus

Specific locations on a chromosome where a gene is found.

True-breeding

Organisms that always pass down a specific phenotypic trait.

Homozygous

An organism with two identical alleles for a trait.

Heterozygous

An organism with two different alleles for a trait.

Dominant allele

An allele that is fully expressed in the phenotype.

Recessive allele

An allele that has no noticeable effect on the organism's appearance.

Law of Segregation

Alleles segregate during meiosis, and each gamete carries only one allele for each gene.

Independent Assortment

Alleles for one gene segregate independently of alleles for another gene.

Test Cross

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

Mendel's F1 Generation

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

Punnett Square

A diagram used to predict the genotype and phenotype outcomes of a genetic cross.

Monohybrid Cross

A cross between individuals that involves one pair of contrasting traits.

Dihybrid Cross

A cross between individuals that involves two pairs of contrasting traits.

Phenotypic Ratio

The ratio of different phenotypes in the offspring from a genetic cross.

Genotypic Ratio

The ratio of different genotypes in the offspring from a genetic cross.

Cystic Fibrosis

A genetic disorder caused by a recessive allele leading to mucus buildup.

Sickle Cell Disease

A genetic disorder caused by a dominant allele affecting red blood cells.

Achondroplasia

A genetic disorder caused by a dominant allele leading to dwarfism.

Polygenic Traits

Traits controlled by two or more genes.

Pleiotropy

A single gene influences multiple phenotypic traits.

Environmentally Influenced Traits

Traits that depend on both genetics and environmental factors.

Chromosome Theory of Inheritance

States that genes are located on chromosomes that segregate during meiosis.

Gregor Mendel

The father of genetics known for his work with pea plants.

Homologous Chromosomes

Chromosomes that carry the same genes but may have different alleles.

Consanguineous Mating

Mating between relatives, increasing the risk of genetic disorders.

Pedigree Analysis

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

Hemophilia

A sex-linked genetic disorder that affects mainly males.

Dominance Hierarchy

The ranking of alleles in terms of expression in the phenotype.

Codominance

A form of dominance where both alleles in a heterozygote are fully expressed.

Incomplete Dominance

A form of inheritance where the phenotype is a blend of both alleles.

Quantitative Inheritance

Variation in phenotype that follows a continuous distribution.

Mendelian Genetics

The study of how genes are inherited through generations according to Mendel's laws.

Chromosome Segregation

The process during meiosis where homologous chromosomes segregate into gametes.

Genetic Linkage

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

Mendel’s Work Rediscovery

Mendel's principles were largely ignored until rediscovered in 1900.

Sex-linked Genes

Genes that are located on the sex chromosomes.

Autosomal Recessive Disorders

Disorders caused by recessive alleles on non-sex chromosomes.

Carriers

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

F2 Generation

The second generation of offspring obtained from a genetic cross.

Segregation of Alleles

The separation of alleles during gamete formation.

Monohybrids

Offspring of a monohybrid cross.

F1 and F2 Definitions

F1 is the first filial generation; F2 is the second filial generation.

Mendel's Laws Reflections

Mendel's laws accurately reflect the behavior of chromosomes during meiosis.

Environmental Influence

Modification of gene expression due to environmental factors.

Dihybrid Cross Resulting Ratios

Typically 9:3:3:1 phenotypic ratio in dihybrid crosses.

Variable expressivity

Variation in degree of phenotypic expression among individuals.