Transposable Elements and Barbara McClintock

The order in which genes involved in a biosynthetic pathway are arranged.

A pathway where a gene mutation disrupts a biological pathway resulting in functional changes.

DNA sequences that can move from one location to another within a genome.

A type of transposable element that copies itself and integrates it at a new location, often involving an RNA intermediate.

A type of transposable element that moves from one location to another in the genome by cutting and pasting themselves.

A point mutation that does not change the amino acid sequence of a protein.

A point mutation that results in a change in the amino acid sequence of a protein.

A point mutation that introduces a premature stop codon, which shortens the protein.

A mutation that shifts the reading frame of the genetic code, altering the amino acid sequence downstream of the mutation.

A mutation that compensates for the effects of another mutation within the same gene.

A mutation that results in a loss of function of a protein.

A condition where one functional copy of a gene is sufficient for normal function.

A condition where one functional copy of a gene is insufficient for normal function.

A mutation that gives a protein a new or enhanced function.

She discovered that genes in maize chromosomes can change position.

A missense mutation where a chemically similar amino acid replaces the original one.

Recognized Barbara McClintock's groundbreaking discoveries.

A missense mutation where a chemically different amino acid replaces the original one.

Scientists used maize to study chromosomes because they are large and visible.

A mutation that alters a single base in the DNA.

McClintock observed that a specific part of chromosome 9 continuously broke.

Mutations affecting the sequences where introns are removed from pre-mRNA, causing splicing errors.

McClintock's work highlighted how genes, or parts of chromosomes, can change their position on chromosomes.

A series of chemical reactions that convert a starting molecule into a final product.

It allows detailed analysis of the genetic material.

A series of chemical reactions that break down a molecule into smaller molecules.

Determining the location and order of genes on chromosomes.

Visual representation of a complete set of chromosomes.

Certain corn strains exhibited breaks in chromosome 9, possibly due to a factor called 'Ds'.

A genetic element in corn that can cause chromosome breakage.

An element needed to activate the Ds element and cause breakage in a specific location.

The Ds element triggers easily observable traits (phenotypes) related to breakage.

Breakage of dominant alleles creates recessive phenotypes.

Genetic elements that do not appear to be located on the same chromosome.

Specific chromosome in corn where breakage frequently occurred.

Observable traits influenced by the Ds element, useful for determining its effect.

A condition where an organism has one less chromosome than the normal diploid number (2N-1).

A genetic condition where an organism has one extra chromosome than the normal diploid number (2N+1).

A condition where an organism has two extra chromosomes than the normal diploid number (2N+2).

A condition where an organism has a complete set of chromosomes, usually in multiples of the haploid number (n).

A condition where an organism has only one set of chromosomes (n).

A cell or organism that has one set of chromosomes (n).

The development of an embryo from an unfertilized egg. It results in an individual with only one set of chromosomes.

Genes that, when homozygous, cause the death of an organism.

A karyotype with three X chromosomes, usually fertile. The third X chromosome does not pair and is not transmitted to offspring.

A karyotype with two X chromosomes and one Y chromosome, resulting in Klinefelter syndrome. One X chromosome is inactivated.

A technique to detect duplications or deletions of at least 50kb pieces of the human genome by comparing a sample DNA with a control DNA on a microarray.

A non-invasive prenatal test that uses ultrasound to measure the fluid under the baby's skin at the back of the neck. Thicker than normal fluid suggests Down syndrome.

An invasive prenatal test that collects villi tissue from the placenta between 10 to 13 weeks of pregnancy for genetic testing.

An invasive prenatal test that collects amniotic fluid from the amniotic sac after 16 weeks of pregnancy for genetic testing.

Tests performed during pregnancy to identify babies at higher risk for certain conditions. These tests are not diagnostic.

Tests performed during pregnancy to definitively diagnose a specific condition. These tests are more invasive.

Chorionic villis sampling has a 1% risk of miscarriage.

A blood test performed on the pregnant woman's blood to detect fetal DNA for certain genetic conditions.

A statistical measure used to determine whether two genetic loci are linked (close together on a chromosome). A higher LOD score indicates stronger evidence for linkage.

Quantitative Trait Loci - Regions of the genome associated with variation in a complex trait that is not completely controlled by a single gene.

Genetically identical lines created by inbreeding individuals from an F2 generation. Each RIL is homozygous at all loci and represents a unique mosaic of maternal and paternal alleles.

Precise localization of a gene or QTL within a specific genomic interval. It uses recombination events in a population to narrow down the target region.

A specific QTL responsible for variation in fruit size in tomatoes, located on chromosome 2.

The study of identifying and characterizing the specific genes and genetic regions that control fruit size in tomato plants.

Genes that are suspected to be involved in a particular trait based on their function or location.

A group of researchers who published a seminal study on the genetic basis of tomato fruit size.

Transposable elements (TEs) can move within a genome, potentially relocating genes closer together or to entirely different locations. This can alter gene expression levels by disrupting regulatory sequences or altering gene proximity.

TE movement can disrupt regulatory elements, leading to changes in gene expression. They can insert near promoters, enhancers, or silencers, influencing the level of transcription of a gene.

Transposons can be harnessed to insert genes of interest into specific locations within a genome. This is often used to create transgenic organisms, such as flies, with new traits.

These chromosomes determine an individual's sex. In humans, females have two X chromosomes (XX), and males have one X and one Y chromosome (XY). The Y chromosome carries genes that specifically determine male characteristics.

A polyploid organism that arises from within a single species. This occurs when chromosomes duplicate during cell division.

An autopolyploid with three sets of chromosomes. They often result from errors in meiosis, leading to a 2n + n = 3n chromosome configuration.

Autotriploids are often sterile due to the formation of aneuploid gametes (gametes with an abnormal number of chromosomes).

Gametes (sperm or egg cells) that have an abnormal number of chromosomes due to errors during meiosis.

A type of cell division that produces gametes (sperm and egg cells) with half the number of chromosomes as the parent cell.

Pairs of chromosomes that have the same genes, one from each parent, which pair up during meiosis.

The exchange of genetic material between homologous chromosomes during meiosis, creating new combinations of alleles.

The random separation of homologous chromosomes into daughter cells during meiosis, leading to genetic diversity.

Sex cells (sperm and egg cells) that contain half the number of chromosomes of a normal cell.

The process of organizing and compacting DNA within the nucleus of a cell to fit into a small space.

The basic unit of DNA packaging, consisting of a segment of DNA wrapped around a core of eight histone proteins.

Small, positively charged proteins that bind to negatively charged DNA, facilitating its packaging.

The dynamic process of altering the structure of chromatin to make DNA more or less accessible for processes like transcription.

A tightly packed form of chromatin where genes are typically silenced, meaning they are not expressed.

The ability of cells to retain patterns of gene expression and chromatin structure even after cell division.

The process of preventing the expression of a gene, often by changes in chromatin structure.

Two new cells produced from a single parent cell through cell division.

Giant chromosomes found in the salivary glands of certain insects, especially fruit flies, that have multiple copies of DNA tightly packed together resulting in a banded appearance.

Polytene chromosomes are used to study changes in chromosome structure, map specific gene locations, and identify genes involved in particular processes by observing changes in banding patterns after hybridization.

Dark bands in polytene chromosomes represent regions with more condensed DNA, which are typically gene-rich.

When sister chromatids in salivary glands undergo replication, the DNA replicates without cell division, leading to multiple copies of DNA packed closely together, resulting in a polytene chromosome with distinctive banding patterns.

Polytene chromosomes provide a fascinating model system for studying chromosome structure, gene organization, and gene expression, particularly in developmental biology.

Polytene chromosomes can be visualized under a light microscope due to their highly condensed and banded structure.

Banding patterns in polytene chromosomes can change due to mutations, deletions, or rearrangements in the chromosomes. These changes can be observed and analyzed to study specific genetic events on a large scale.

By observing changes in the banding patterns of polytene chromosomes after hybridization with specific DNA probes, scientists can map the location of particular genes and identify genes involved in specific traits.