Linkage and Recombination Flashcards
Cellular structures that carry genes
Chromosomes
A diagram that describes the order of genes along a chromosome
Genetic Map
Functional units that influence an organism’s traits
Genes
Occurs when two or more genes are located on the same chromosome
Synteny
The phenomenon in which genes that are close together on the same chromosome tend to be transmitted as a unit
Genetic Linkage
(or Linkage)
A chromosome that contains a group of genes that are physically linked together
Linkage Groups
They (2) carried out a study indicating that some characters may not assort independently
- William Bateson
- Reginald Punnett
A phenomenon wherein homologous chromosome exchange pieces with each other
Crossing Over
Crossing Over
The replicated chromosomes, known as […], associate with their homologs to form a structure known as a […]
- sister chromatids
- bivalent
When does crossing over occur?
Prophase I
Haploid cells that contain the same combination of alleles as the original chromosomes
Nonrecombinant Cells
Haploid cells that carry a different combination alleles from the original chromosomes
Recombinant Cells
If recombinant cells participate in fertilization, the resulting offspring are called […]
recombinant offspring
Occurs when offspring inherit a combination of two or more alleles or traits that are different from those in either parent
Genetic Recombination
[…] are produced by the exchange of DNA between two homologous chromosomes during meiosis in one or both parents, leading to a novel combination of genetic material
Recombinant offspring
He brought the first direct evidence that different genes are physically located on the same chromosome
Thomas Hunt Morgan
He investigated the inheritance of different traits that had been shown to follow an X-linked pattern of inheritance
Thomas Hunt Morgan
Observed chiasmata under the microscope and proposed that crossing over involves a physical exchange between homologous chromosomes
Frans Alfons Janssens
The likelihood of crossing over depends on the […] between two genes
distance
If two genes are far apart from each other, crossing over is more likely to […]
occur between them than between two genes that are close together
This can be employed to determine if the outcome of a two-factor cross is consistent with linkage or independent assortment
Chi Square Test
Chi Square Test
If the chi square value is low and we cannot reject the null hypothesis, we infer that the genes […]
assort independently
Chi Square Test
If the chi square value is high and we reject the null hypothesis, we infer that the genes […]
are linked
They (2) used an interesting strategy involving parallel observations to obtain direct evidence that crossing over can result in genetic recombination
- Harriet Creighton
- Barbara McClintock
Used to determine the linear order and distance of separation among genes that are linked to each other on the same chromosome
Genetic Mapping
The site where the gene is found within a particular chromosome
Locus
Why is genetic mapping useful?
- To understand the overall complexity and organisms of a genome
- To know the locus of a gene, allowing cloning and studying
- To understand evolutionary relationships
- To diagnose and treat inherited diseases
- To improve agriculturally important strains through selective breeding programs
Includes techniques that involve an analysis of crosses of individuals that are heterozygous for two or more genes
Traditional Genetic Mapping
The figure that depicts the linear arrangement of genes
Genetic Linkage Map
The units of map distance are called […] or […]
- map units (mu)
- centiMorgans (cM)
One map unit is equivalent to a […]
1% frequency of recombination
A […] is always expected to cause the least frequent types of offspring
double crossover
An event that may produce a pair of recombinant chromosomes that have a new combination of alleles
Mitotic Recombination
He identified unusual patches on the bodies of flies from certain Drosophila strains
Curt Stern
Two adjacent regions which are different from the rest of the body
Twin Spot
