Genetics Final

Drosophila sex cascade

C. Elegans sex cascade

Tra-1 expression high, hermaphrodite

Tra-1 expression low, male

Genes that increase cell division

Ras - activates kinase, promotes proliferation

Bcl2 - blocks apoptosis

EF2 - transcription factor, promotes proliferation

lf decrease, gf increase

Genes that block cell division

P53 - tumor suppressor

P21 - blocks cell cycle

Rb - tumor suppressor

lf increase, gf decrease

FISH

FISH (Fluorescence In Situ Hybridization) is a laboratory technique used to detect and locate specific DNA sequences on chromosomes. It uses fluorescently labeled probes that bind to complementary sequences, allowing researchers to visualize gene locations, chromosomal abnormalities, or structural changes in cells under a microscope.

Domain

a distinct functional region of a protein, often responsible for specific tasks like binding to other molecules or catalyzing chemical reactions

Paralog

A paralog is a gene that arises through duplication within the same organism’s genome and evolves to perform a related but slightly different function. Paralogs are part of the same gene family but may have distinct roles.

Simple nucleotide polymorphism (snp)

A SNP (Single Nucleotide Polymorphism) is a variation at a single position in the DNA sequence among individuals. For example, one person might have an "A" at a specific location in their DNA, while another has a "G". SNPs can affect traits, disease risks, or have no noticeable effect at all.

Simple sequence repeat (ssr)

An SSR (Simple Sequence Repeat), also called a microsatellite, is a short sequence of DNA (usually 2–6 base pairs) that repeats multiple times in a row. For example, "ACACACAC." SSRs are highly variable between individuals and are often used in genetic studies, like DNA fingerprinting or population genetics.

Restriction fragment length

A restriction fragment length refers to the size of a DNA segment generated when a DNA molecule is cut by a specific restriction enzyme. The length of these fragments depends on the location of the enzyme's recognition sites in the DNA. This concept is commonly used in techniques like Restriction Fragment Length Polymorphism (RFLP) to study genetic variation.

Polymorphism (RFLP)

Polymorphism (RFLP) stands for Restriction Fragment Length Polymorphism. It is a variation in DNA sequence that changes the location of restriction enzyme recognition sites. This leads to differences in the lengths of DNA fragments when the DNA is cut by the enzyme. RFLP is used in genetic mapping, identifying genetic diversity, and detecting inherited diseases.

Alternative splicing

Alternative splicing is a process where a single gene can produce multiple different proteins. This happens because the gene's RNA can be "cut and pasted" in various ways, using different combinations of exons (coding regions). As a result, one gene can lead to the creation of multiple protein variants with potentially different functions.

Pseudogene

a non functional copy of a gene

Gene desert

a region of the genome that has very few or no genes. large, non-coding regions of DNA with little to no function in producing proteins.

Yeast two-hybrid screen

A yeast two-hybrid screen is a laboratory technique used to study protein-protein interactions. It involves two key proteins being expressed in yeast cells. One protein is fused to a "bait" molecule, and the other to a "prey" molecule. If the two proteins interact, they bring together two components of a reporter system, leading to a detectable signal (like growth or color change). This allows researchers to identify interacting proteins.

Transposon

A transposon is a DNA sequence that can move or "jump" from one location to another within the genome

Retrotransposon

A retrotransposon is a type of transposon that moves within the genome by first being transcribed into RNA, then reverse-transcribed back into DNA, and finally inserted into a new location in the genome.

replicative transposition

Replicative transposition is a type of transposon movement where the transposon is copied and the copy is inserted into a new location in the genome, while the original copy remains in its original location.

DNA Transposon

A transposon that moves by "cut-and-paste" without an RNA intermediate.

conservative transposition

Conservative transposition is a process by which a transposon moves from one location in the genome to another without being copied

environmental mutagen

An environmental mutagen is a physical or chemical agent from the environment that can cause changes (mutations) in the DNA of organisms.

Oncogene

Gene associated with cancer, mutations usually dominant, activate gene/protein

Proto-oncogene

Normal gene that could turn into cancer, often function to control proliferation

Tumor suppressor

Genes whos products protect cells from becoming cancerous

Metastasis

Cells can spread to new sites

Cyclin

Protein whos level changes throughout cell cycle

CDK

Cyclin dependent kinase (kinases add phosphate to target proteins)

checkpoint

Cell determines if it ready for next phase in cell cycle

Apoptosis

Programmed cell death

Caspase

A protease that can mediate apoptosis

familial adenomatous polyposis coli

mutation in APC, protein degrades cytoplasmic B-catenin

Mutant APC, loses wild type, can’t degrade B-catenin, becomes cancerous

loss of heterozygosity

Loss of heterozygosity (LOH) occurs when one allele of a gene is lost or silenced, leaving a cell or organism with two identical copies of a gene (homozygosity) instead of two different alleles (heterozygosity). LOH is often associated with cancer, where the loss of a tumor-suppressor gene can contribute to uncontrolled cell growth.

Li-Fraumeni syndrome

Mutation in P53 gene, higher risk of many types of cancer

Can’t institute DNA damage checkpoint, can’t induce apoptosis if damage isn’t repaired

Sex determination

Sex determination is the biological process by which an organism’s sex is established, typically based on its genetic makeup. In many species, it is determined by specific sex chromosomes (e.g., XX for females and XY for males in humans). The presence or absence of certain genes, such as the Sry gene on the Y chromosome, influences the development of male or female traits.

SRY

Sry (Sex-determining region Y) is a gene located on the Y chromosome that plays a crucial role in determining male sex. It initiates the development of male characteristics by triggering the formation of testes, which produce male hormones (androgens) that lead to the development of male physical traits.

Dosage compensation

A process that equalizes gene expression form sex chromosomes in males and females

Morphogen

A morphogen is a signaling molecule that helps control the pattern of tissue development by diffusing across cells and triggering specific gene expression based on its concentration.

Gap genes

Gap genes are a group of genes that control the development of broad regions of an organism's body during early embryonic development. They define large segments along the anterior-posterior axis and help establish the basic body plan.

Segment polarity genes

Segment polarity genes are genes that control the development of individual segments in the body of an organism, particularly during early development. They help establish the anterior-posterior polarity within each segment, determining the structure and identity of parts of the organism’s body.

Homeosis

Homeosis is the phenomenon where one body part is transformed into another, usually due to mutations in homeotic genes. These genes control the development of specific body regions, and their alteration can lead to the misdevelopment of structures, such as legs growing where antennae should be.

Equivalence group

An equivalence group refers to a group of cells or tissues in early development that have the potential to develop into the same type of structure or organ, depending on signals they receive. These cells are considered "equivalent" because they can give rise to the same outcome under different conditions.

Population

A population is a group of individuals of the same species that live in a specific geographic area and interbreed, sharing a gene pool.

Subpopulation

A subpopulation is a smaller, distinct group within a larger population, often separated by geographic, environmental, or behavioral factors, but still belonging to the same species.

Gene pool

A gene pool is the total collection of genes and alleles present in a population or species, representing the genetic diversity available for inheritance.

Hardy-Weinberg

Hardy-Weinberg refers to the Hardy-Weinberg equilibrium, a principle that states that allele frequencies in a population will remain constant from generation to generation in the absence of evolutionary forces (such as mutation, natural selection, genetic drift, or gene flow). It provides a baseline to study genetic changes in populations.

Mating system

A mating system is the way in which a species mates, including how individuals pair up and reproduce. Common mating systems include monogamy (one male and one female), polygyny (one male mates with multiple females), polyandry (one female mates with multiple males), and promiscuity (individuals mate with multiple partners without forming long-term bonds).

Assortative mating (positive or negative)

Assortative mating is a mating pattern where individuals tend to mate with others that are similar (positive assortative mating) or different (negative assortative mating) from themselves in specific traits.

- Positive assortative mating: Individuals with similar traits (e.g., height, color) are more likely to mate.

- Negative assortative mating: Individuals with different traits are more likely to mate.

Inbreeding

Inbreeding is the mating of individuals that are closely related genetically, leading to an increased probability of offspring inheriting similar genetic material from both parents. This can result in a higher chance of genetic disorders and reduced genetic diversity.

Multi factorial traits

Multifactorial traits are traits influenced by multiple genetic factors (genes) and environmental factors. These traits show continuous variation (e.g., height, skin color, and intelligence) rather than discrete categories. The interaction between genes and the environment determines the expression of these traits.

Quantitative traits

Quantitative traits are traits that vary in degree and are measured on a continuous scale, such as height, weight, or blood pressure. These traits are influenced by multiple genes and environmental factors, leading to a range of phenotypes rather than distinct categories.

Variance

Variance is a statistical measure of how much individual values in a dataset differ from the mean (average) of the dataset. It quantifies the degree of variation or spread in a set of values. High variance means the values are spread out, while low variance indicates they are close to the mean.

Total variance

Total variance is the overall measure of variability in a dataset, accounting for all sources of variation. It is the sum of genetic variance (variation due to genetic differences) and environmental variance (variation due to environmental factors) in traits. It represents how much individuals in a population differ from the overall mean for a particular trait.

Environmental variance

Environmental variance is the portion of total variance in a trait that is caused by differences in the environment rather than genetic differences. It reflects how environmental factors (like diet, climate, or upbringing) contribute to variations in the expression of a trait within a population.

Genetic variance

Genetic variance is the portion of total variance in a trait that is due to differences in the genetic makeup of individuals within a population. It reflects how genetic differences, such as alleles and gene interactions, contribute to the variation in a trait.

Heritability

Heritability is the proportion of the total variation in a trait that is due to genetic factors. It quantifies how much of the variation in a trait within a population can be attributed to genetic differences, as opposed to environmental factors. Heritability values range from 0 (no genetic influence) to 1 (all variation is genetic).

Linkage equilibrium

Linkage equilibrium refers to a situation in a population where alleles at different loci (gene positions) are inherited independently of each other. In this state, the allele combinations at two or more loci occur at frequencies predicted by the product of their individual allele frequencies. It implies that there is no physical or genetic association between the loci.

Genome wide association study

A Genome-Wide Association Study (GWAS) is a research method used to identify genetic variants (like SNPs) associated with specific traits or diseases by scanning the entire genome of many individuals. It compares the genetic makeup of individuals with and without a particular trait to find correlations between certain genetic markers and the trait of interest.