Genetic Inheritance and Cancer Biology Flashcards

Flashcards on Genetic Inheritance Patterns, Cancer Biology, and Genetic Mutations

Monozygotic twins

Twins that share 100% of their genes; concordance for single-gene disorders should ideally be 100%

Dizygotic twins

Twins that share about 50% of their genes; concordance for recessive single-gene disorders is typically lower, often around 25%.

Specific age of onset

Suggests a genetic cause, as many genetic disorders manifest at particular life stages.

Autosomal recessive

Showing 25% of children from two unaffected heterozygous parents affected indicates this inheritance pattern.

Autosomal dominant

Traits that typically show affected individuals in every generation.

Recessive traits

Traits can skip generations.

X-linked recessive inheritance

Leads to a higher prevalence of the disease in males; males only have one X chromosome, so a recessive gene on that chromosome will cause the disease.

Tumor suppressor genes

Inhibit cell cycle progression (BRAKE PEDALS)

Oncogenes

Promote cell cycle progression (GAS PEDAL), leading to uncontrolled cell growth.

Mutations in oncogenes

Often result in gain-of-function

Mutations in tumor suppressor genes

Typically lead to loss-of-function.

Dominant negative mutation

A type of mutation where the mutant gene product interferes with the function of the wild-type (normal) gene product, even when the wild-type gene is present.

Dominant negative mutation

Occurs in tumor suppressor genes, like p53

Haploinsufficiency

A genetic phenomenon where a single copy of a functional gene is not sufficient to produce a normal phenotype.

Oncogenic form of Ras

Characterized by decreased GTPase activity, leading to prolonged signaling and increased cell proliferation.

Amplifications of oncogenes

Can lead to overexpression, contributing to cancer development.

Caspases

Enzymes that play a key role in apoptosis, the programmed cell death process, which is often disrupted in cancer.

Epigenetic changes

Can alter gene expression without changing the DNA sequence, contributing to cancer progression.

DNA methylation and histone modifications

Key mechanisms of epigenetic regulation that can activate or silence genes, impacting cancer development.

Environmental influences, diet, and lifestyle

Can lead to epigenetic modifications.

Hepatitis B virus and Papillomavirus

Contribute to cancer development in humans.

Rous sarcoma virus

A classic example of a virus that can induce cancer in animals, providing insights into viral oncogenesis.