Mendelian and Non-Mendelian Inheritance

A pattern of inheritance where both alleles for a trait are expressed equally in the offspring, resulting in a phenotype that combines both parental traits.

A cross between a black-furred male dog and a white-furred female dog could produce an offspring with a black-and-white coat.

A cross between a red flower and a white flower can result in a flower with both red and white patches.

A form of inheritance where one allele is not completely dominant over another, resulting in a blended phenotype.

When red and white snapdragons are cross-pollinated, the resulting offspring are all pink.

The F2 generation of snapdragons, resulting from self-pollination of pink flowers, will have a phenotypic ratio of 1:2:1, with red, pink, and white flowers.

The F2 generation of snapdragons, resulting from a cross between pink flowers and true-breeding red flowers, shows a 1:1 ratio of red and pink flowers.

A monohybrid cross is a cross between two individuals that differ in only one trait.

When a black chicken and a white chicken reproduce, the offspring will have blue feathers. Neither color is completely dominant.

A cross between a long-haired Angora rabbit and a short-haired Rex rabbit produces offspring with fur of an intermediate length, longer than Rex but shorter than Angora.

When a long-tailed dog and a short-tailed dog reproduce, the offspring often have tails of medium length, demonstrating incomplete dominance.

Labradoodles with wavy hair are a result of incomplete dominance. Their parents have straight and curly hair, leading to an intermediate wavy coat.

The cream gene in horses, when paired with a red allele, produces golden coats, such as palominos and buckskins.

The study of genetics began with plants, where people have been breeding for desirable traits for thousands of years.

Josef Kolreuter discovered incomplete dominance by breeding red and white carnations, resulting in pink offspring.

A pattern of inheritance where neither allele for a trait is completely dominant over the other, resulting in a blended phenotype.

A heterozygous individual with incomplete dominance will have a phenotype intermediate to the two homozygous parents. For example, a red flower and a white flower might produce a pink flower.

The offspring will have a 1:2:1 ratio of phenotypes: 1/4 will exhibit the dominant allele phenotype, 1/4 will exhibit the other dominant allele phenotype, and 1/2 will exhibit the intermediate, blended phenotype.

Snapdragons with red flowers (RR) and white flowers (WW) produce pink flowers (RW) when crossed.

The color of eggplants, with purple and white parent plants producing light violet offspring, showcasing incomplete dominance.

Familial hypercholesterolemia (FH), a disease where one allele doesn't produce enough cholesterol receptors, resulting in a partial deficiency and a higher risk of heart disease.

When one parent has straight hair and the other has curly hair, their offspring might have wavy hair, demonstrating incomplete dominance in hair texture.

Incomplete dominance plays a crucial role in improving crops like corn, where multiple genes contribute to traits like health and yield. This 'hybrid vigor' is a result of incomplete dominance.

Different versions of a gene, responsible for variations in traits.

A situation where a gene has more than two alleles.

A gene with multiple alleles, meaning there are at least two possible alleles.

A type of inheritance where multiple genes contribute to a single trait.

Each gene involved in polygenic inheritance has a small, additive effect on the trait.

Traits influenced by polygenic inheritance have a continuous range of variation.

The ABO blood group system in humans is controlled by three alleles: IA, IB, and i.

In polygenic inheritance, genes work together additively, without one masking the other.

A type of inheritance where multiple genes, each with contributing alleles, influence a single trait.

Polygenic traits show a continuous range of phenotypes, not distinct categories.

Because of the complex interplay of many genes, it's difficult to predict the exact phenotype of an individual.

Alleles contributing to a trait are considered 'active', while those not affecting the trait are 'null'.

Skin color in humans is a classic example of a polygenic trait, with many genes contributing to its variation.

Height is determined by hundreds of genes and also influenced greatly by environmental factors.

Eye color is a polygenic trait, with multiple genes contributing to the variety of eye colors, including at least 9 recognized colors.

In a specific wheat example, three genes contribute to red pigment, with each gene having two alleles - one producing pigment (uppercase) and one not (lowercase). The number of uppercase alleles determines the intensity of red.

A trait expressed in both males and females who inherit the abnormal gene on the X chromosome.

A rare pattern of inheritance where a gene on the X chromosome is dominant, causing the trait to be expressed in both males and females who inherit the abnormal gene.

An allele is dominant in one sex but recessive in the other. This can be caused by hormonal differences between sexes.

An autosomal gene for hair growth pattern has two alleles: one for hair growth and one for baldness. The baldness allele is dominant in males but recessive in females.

A trait that affects a structure or function of the body present only in males or females. The gene for the trait can be X-linked or autosomal.

Beard growth in humans is sex-limited. Women cannot grow beards because they lack the necessary hormones.

A genetic condition that causes muscle degeneration, the most common and severe form of muscular dystrophy. It quickly worsens and is fatal.

A condition that results in learning, behavioral, and intellectual disabilities. It affects about 1 in 4,000 males and 1 in 8,000 females.