Introduction to Genetics in Biology 305

Photic Sneeze Reflex

Genetic trait causing sneezing in bright light.

Epigenetics

heritable changes in gene expression that occur without changes to DNA; is reversible; can be influenced by the environment; DNA Methly

Meiosis I: Prophase I

Chromosomes condense, homologous chromosomes pair up, the membrane breaks down, and spindles form. Cross over occurs

Genetics

Study of heredity and inherited characteristics.

Genetic Material

Molecules encoding, replicating, and expressing heredity.

Transmission of Inheritance

Patterns through which traits are passed to offspring.

Molecular Biology

Study of biological processes at the molecular level.

Gene Expression

Process by which information from genes is used.

Genetic Variation

Differences in DNA sequences among individuals.

Model Organisms

Species used for genetic analysis due to specific traits.

Bioinformatics

Use of software tools to analyze biological data.

GWAS

Genome-wide association studies linking genes to traits.

Sickle Cell Anemia

Disease caused by a single genetic mutation.

CRISPR-Cas

Gene editing technology for precise DNA modifications.

Recombinant DNA

DNA formed by combining genetic material from different sources.

Alleles

Different versions of a gene at a locus.

Phenotypes

Observable traits resulting from gene expression.

Germplasm Theory

Concept that heredity is transmitted through germ cells.

PCR

Technique to amplify specific DNA sequences.

Gene Therapy

Treatment aiming to correct defective genes.

Synthetic Organisms

Organisms created with engineered genetic material.

Evolutionary Theory

Framework explaining the diversity of life through genetics.

DNA Sequencing

Determining the precise order of nucleotides in DNA.

RNA-based Vaccines

Vaccines designed using RNA to provoke immune response.

Human Genome Project

International effort to map all human genes.

Genetic Association Studies

Research linking genetic variations to specific traits.

Genetics in Society

Modern medicine, understanding genetic disorders, personalized treatment, GMO agriculture, selective animal breeding, Forensic science, conservation

Aristotle Genetics Theory

"Form" from the father and "matter" from the mother. He believed that environmental factors could affect the ultimate result.

Preformationism

inside egg or sperm is a tiny version of an adult (homunculus)

blending inheritance

An outdated, disreputed theory that the phenotype of an offspring was a uniform blend of the parent's phenotypes.

Pangenisis Theory

A genetics theory that Darwin Believed

Germplasm

Weisman's Genetic Theory

Gregor Mendel

Peaplant research laid the foundations for modern genetics. Disproved blending inheritance theory, and highlighted the presence of dominant and recessive alleles. Helped develop Cell Theory.

Gregor Mendel Time Line

Conducted research in the late 1800s. Died in obscurity, and then his research was rediscovered by Tschermak in the early 1900s.

Chromosome Structure

Picture

cell theory

idea that all living things are composed of cells, cells are the basic units of structure and function in living things, and new cells are produced from existing cells

kineticore

a disc shaped protein found in the centromoere region of a chromosome and attaches the chromosome to the mitotic spindle

Spindle Microtuble

microtubules organized in a spindle shape that separate chromosomes during mitosis or meiosis

Centromere

Area where the chromatids of a chromosome are attached

sister chromatids

joined copies of the original chromosome

Telomere

repetitive DNA at the end of a eukaryotic chromosome used for protection (end of a shoelace)

Eukaryotes

organisms made up of one or more cells that have a nucleus and membrane-bound organelles; linear DNA; Plants and Animals

Prokaryote

A unicellular organism that lacks a nucleus and membrane bound organelles; DNA is free flowing or circular; bacteria and archea

Transcription

(genetics) the organic process whereby the DNA sequence in a gene is copied into mRNA

Translation

Process by which mRNA is decoded and a protein is produced

DNA

A complex molecule containing the genetic information that makes up the chromosomes.

Gene

A segment of DNA on a chromosome that codes for a specific trait

Chromosome

a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.

Chromatin structure

DNA + Histone proteins (look up image); (chromosomes are made of chromatin in a much more condensed form)

Phenotypes

Are affected by genes, gene interactions, development, and the eviorment

Mutations

Passed on during cell replication

Insertion

A mutation involving the addition of one or more nucleotide pairs to a gene.

Deletion

A change to a chromosome in which a fragment of the chromosome is removed.

inversion mutation

Reversing of Gene order; recombination is reduced; if it does occur the gametes are often nonviable

Translocation

piece of a chromosome moves to another chromosome (fragile (repeated areas) are more likely to experience translocation)

Evolution

Change in frequency of alleles in a population over time

Bacteria Chromosome Replication

Binary fission

Homologous Pairs

A pair of chromosomes of the same type, one from each parent.

Diploid

2 sets of chromosomes; have the same genes but potentially different alleles on those genes

Halploid

contains one set of chromosomes

Polyploid

condition in which an organism has extra sets of chromosomes

submetacentric chromosome

Chromosome in which the centromere is displaced toward one end, producing a short arm and a long arm (LOOK UP IMAGE)

metacentric chromosome

centromere is in the middle (LOOK UP IMAGE)

telocentric chromosome

Chromosome in which the centromere is at or very near one end.(LOOK UP IMAGE)

Arocentric chromosome

centromere close to end (LOOK UP IMAGE)

Cell Cycle

series of events that cells go through as they grow and divide

Interphase

the cell grows and devlops

G1 phase

cell gets larger, proteins are synthesized

G0 phase

Cell is stable, soon renters G1

Check points

Places in the cell cycle that control whether the cell will divide

S phase

DNA is copied in each chromosome (2 sister chromatids)

Chohesin

A ring-shaped protein that keeps sister chromatids together.

G2 phase

cell prepares for mitosis

Interphase time line

23 hours ; difficult to see chromosomes

M phase (mitosis)

prophase, metaphase, anaphase, telophase

Prophase

Condensin proteins bind DNA and condense into chromosomes (easy to see under microscope); Miotic spindle forms from microtubles

Condensin

proteins that help sister chromatids coil during prophase

mitotic spindle

An assemblage of microtubules and associated proteins that is involved in the movements of chromosomes during mitosis.

microtubles

long strands such a spindle fibers that move chromosomes (made of Tubulin)

Prometaphase

disintegration of the nuclear envelope; spindles enter the nuclear region, and chromosomes become anchored by a centrosome from 1 pole attacking to the kinetochore of a chromatid.

Metaphase

chromsomes align down the middle. Tension grows from spindle fibers pulling each side.

Anaphase

connection between chromatids disolves; microtubes cause splitting of chromatids, Cohesin protein breaks down

Telophase

chromosomes arrive at poles, 2 nuclear envelopes form, cytokinesis, chromosomes no longer visible.

Cytokinesis

division of the cytoplasm (cytoplasm does not split equally)

Crossing Over

Process in which homologous chromosomes exchange portions of their chromatids during meiosis, and produces recombination

Metaphase/Anaphase

Homologous pairs are pulled apart but chromatids stay together due to Shugoshin protein. Random splitting creates variation

Shugoshin

A protein implicated in the protection of cohesiveness of sister chromatids to the centromeres during the process of meiosis and in kinetochore regulation during mitosis and meiosis.

Telophase I (Meiosis)

chromosomes arrive at poles

Meiosis II

Very similar to mitosis, however, you finish with 4 haploids

Anaphase II (Meiosis only)

Shugoshin no longer protects chromatids, and the seperation of chromatids occurs

Meiosis differences from Mitosis

4 cells; half the chromosomes; different cells; crossing over; random distriubtion; over all more variation

Physical entities of genes

Specific segments of DNA that determine traits

Wild Type

the phenotype for a character most commonly observed in natural populations

dihybrid cross

A cross between individuals that have different alleles for the same gene (A common ratio is 9:3:3:1)

9:3:3:1 phenotypic ratio

Ratio representing possible set of alleles of a dihybrid cross

Male Sex Chromosomes

XY

Female Sex Chromosomes

XX

Biological Sex determination

determined by sex chromosomes; many different types within the animal kingdom

hermaphrodite

an organism that has both male and female sexes (many flowering plants)

monoecious

reproductive structures from both sexes present