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Genetics exam 2 (Chapters 6-10)
Terms in this set (124)
two or more genes located on the same chromosome
- two genes located on the same chromosome
Genes that are ______ tend to be transmitted from parent to offspring together.
Genes that are farther apart have a _______ chance on being separated during _______ .
greater; crossing over
Chromosomes are often called ___________.
In humans, there are 22 ____________ linkage groups, an _________ group, and a __________ group.
autosomal; X linkage; Y linkage
Who were the first researchers to demonstrate that not all traits assort independently? (2)
Bateson and Punnett
___________ may alter linkage of genes.
___________________ by crossing over can produce new combinations of alleles on chromosomes.
The cells that contain the new allelic combinations are called _______________ or recombinant cells.
The cells that contain the original combination of alleles are called ___________ offspring or non recombinant offspring.
Which researcher provided evidence for the linkage of X-linkage genes and proposed that crossing over between X Chromosomes can occur?
Morgan discovered that _________ between x chromosomes can occur?
Morgan's experimental proof included what 3 things?
body color, eye color, and wing shape of flies
Morgan suggested that body color, eye color, and wing shape were found on the ___________ and are inherited as a ___________.
X chromosome; unit
For offspring that did not contain the parental combinations, Morgan suggested that there was crossing over between the _____________ x chromosomes.
The concept of homologous crossing over had been previously introduced by the French cytologist _______________.
Genes that are __________ are more likely to cross over than genes that are ________.
far apart; close together
The more __________ offspring present, the further apart the genes are.
__________ crossovers between two genes which are far apart can rarely occur as well.
_________ test allows a researcher to test the goodness of fit between the observed and expected data.
How do you test for linkage using a chi square test? (4 steps)
1) Propose a hypothesis.
2) Calculate the expected values for each phenotype.
3) Perform a chi square using the expected values and observed data.
4)Interpret the chi-square.
Which researchers showed that crossing over produced new combinations of alleles and resulted in the exchange of segments between homologous chromosomes?
Creighton and McClintock
Creighton and McClintock are responsible for providing evidence that crossing over is associated with ____________.
Creighton and McClintock identified two abnormalities to track movement of chromosomes:
1) unusual staining pattern or translocations
2) used abnormalities to trace the movement of alleles for kernel color and texture of kernal endosperm
Curt Stern researched crosses in _________.
Genetic ___________ determines the linear order of genes on a chromosome and the separation of those genes on the chromosome.
Genetic maps serve to do the following:
1) allows geneticists to understand complexity and genetic organization of a species
2) illustrates the underlying basis for inherited traits of an organism
3) allows use of molecular techniques to clone/study genes
4) allows possible diagnosis and treatment
5)allows for prediction of likelihood parents will produce offspring with a certain trait/disease
7) enhance selective breeding in agriculture
The linear order of genes on the chromosome is called a ______________.
genetic linkage map.
A _________ is conducted to produce a genetic linkage map.
testcrosses typically include a ____________ individual and a ______________ recessive individual for the traits being mapped.
Nonrecombinant offspring have the same combinations of alleles as one of the _____________ strains.
Non recombinant is to ________(parental/nonparental) and recombinant is to (nonparental/parental).
Crossing over during meiosis produces __________________ (nonrecombinant/recombinant) offspring.
Recombinant offspring are typically _______ (greater/fewer) in number than nonrecombinant offspring.
Map distance is defined as:
the number of recombinant offspring divided by the total number of offspring, multiplied by 100.
Units for map distance are called __________ (mu) or _____________ (cM), which equals a 1% recombination frequency.
map units; centiMorgan
First genetic map constructed by
Strurtevant used ___________ as the model system.
At map distances approaching _____% recombination, there is a greater chance that undetected mulitple crossover events may be influencing the results.
_________ crosses can be used to determine the order and distance between linked genes.
How to perform tryhybrid cross?
1) cross 2 true-breeding strains with 3 alleles
2) cross F1 female heterozygotes to homozygous recessive males for all 3 alleles
3)collect F2 data
4)calculate map distance
The probability of a double-crossover in a trihybrid cross is equal to the product of the ____________ frequency between the genes.
How to calculate Coefficient of Coincidence (C):
observed number of crossovers divided by the expected number of crossovers
Interference is then equal to:
Positive interfernce indicates a ____________ in the observed number of double crossovers comapred to the expected
Negative interference indicates a crossover __________ (enhances/dehances) the chance of a second crossover event occurring in the region.
Simples eukaryotes spend a portion of their life cycle as a (haploid/diploid) ___________ organism.
When a diploid zygote goes through meiosis and produces four haploid cells, the four cells are collectively called a ______.
Stern's study revealed that mitotic recombination is what produces __________.
Cytogenecists study variations in chromosome __________ and __________.
Chromosomes are named according to the location of their ____________.
Based on the location of the centromere, the chromosome is either ccalled:
metacentric, submetacentric, telocentric
All chromosomes have a long arm, called __, and a short arm, called __.
A __________is a micrograph that arranges the chromosomes with the short arm at the top, then descending order by size.
The use of ________ produces a G bonding pattern.
Changes in chromosome structure can change _______ of genetic material or ___________ of the material.
total amount; arrangement
____________ decrease the total genetic content of the chromosome.
Deficiencies and deletions
_____________ doubles the total genetic content of the chromosome.
__________ changes the arrangement of the chromosome.
Two types of _____________ changes the arrangement of the chromosome and the total genetic content.
____________ (Loss/Gain) of genetic material in a deletion tends to be detrimenta to an organism.
Chromosomal deficiencies are the result of a __________ in chromosomes.
After a break in a chromosome, the piece without a centromere is lost, which is called a ________________.
If a chromosome breaks in two different spots and the end pieces rejoins, it is called ________________.
______________ may also cause deficiencies.
Effect of a deficiency depends on the ______ of the deletion.
_____________ tend to be less harmful than deletions.
Duplications are usually the result of incorrect _______________ events.
________________ are usually rare, spontaneous events that occue the evolution of the species.
Repetitive sequences can be sites of __________.
Misalignment can also be considered as ________________________________.
nonallelic homologous recombination
Cri-du-chat syndrome in humans is cause by a ____________ in the short arm of chromosome 5.
Charcot-Marie-Tooth disease is an example of ______________ in humans.
____________ may be responsible for the creation of gene families.
Genes that are derived from a single ancestral gene are called ____________.
Homologous genes in a single species are called __________.
Globin gene family in humans is an example of _____________.
If a homologous chromosome contains two copies of a particular gene, it is said to have undergone ______________________.
Some ____________ may have no phenotypic consequences, while others are associated with specific human disease.
copy number variations
Deletions and duplications are often associated with ___________.
Comparative genomic ________________ allows detection of abnormalities.
Steps of genomic hybrization:
1) chromosomes in metaphase are extracted and labeled red
2) chromosomes from cancer cells in metaphase and fluorescently labeled green
3) DNA from both is denatured and hybridized to each other
4) Any region without a 1:1 ratio of red to green indicates an abnormality in the cancer cell chromosomes
Any region without a ________ ratio of red to green indicates an abnormality in cancer cell chromosomes.
____________ often occur without phenotypic consequences.
An inversion that contains the centromere is called a ____________ inversion.
An ___________ may disrupt the function of a vital gene or may reposition a gene in a way that the gene's level of expression is altered.
repostioning of genes that leads to altered expression are called a ______________-.
During meiosis, the homologous chromosomes form an ___________.
Pericentric inversion results in
2 normal chromosomes and 2 abnormal chromosomes (1 deletion and 1 duplication)
results in 2 normal chromosomes and 2 chromosomes that possess deletions
An individual who carries one copy of an inverted chromosome is called an ________________________________.
________________ involve exchanges between different chromosomes.
The ends of chromosomes have ______________, which contain specialized repetitive DNA.
Abnormal crossover may result in a ____________________.
If a piece of one chromosome is attached to another, it is called an _________________ translocation.
Familial Down Syndrome is an example of ____________.
Individuals with reciprocal translocations may produce abnormal gametes due to the ______________ of chromosomes.
In adjacent-1 and adjacent-2 segregation, the end result is ___________.
four unbalanced gametes
An individual who does not produce 100% normal gametes is said to exhibiy _____________.
Organism that are ______________ have a chromosome number that is an exact multiple of the chromosome set.
An organism with three multiples of the chromosome set is called __________
An organism with three or more sets of chromosomes is called ____________.
_________________ refers to the change in number of a chromosome.
______________ (2n +1) indicates an extra copy of one chromosome.
__________________ (2n-1) indicates a missing copy of one chromosome.
A gene present in three copies may produce ______% of the gene product.
A gene present in on ecopy may produce __% of the gene product.
Almost 50% of spontaneous abortions are due to ___________.
Changes in number of X chromosomes are usually nonlethal, due to the formation of inactive _________.
_____ of the parents may also influence the formation of an aneuploid condition.
ex: male bees are monoploid and female bees are diploids
ex: liver cells in humans are triploid, tetraploid, or octoploid
Polytene chromosomes can contain up to _____ sets of chromosomes.
The central location to which the replicated chromosome aggregates is called the _____________.
Polyploids with an odd numuber of chromosome sets are usually ____________.
Interspecies crosses can create _________
Variations in chromosome number are due to ____________ of the chromosomes.
Non disjunction in meiosis ___ is more detrimentak than it is in meiosis ____.
________________or chromosome loss can produce a patch of tissue with an altered chromosome number.
____________ is the result in an organism whose contain a group of cells that are genetically different from one another.
____________ refers to an increase in the number of chromosome sets in a single species.
Allopolyploid contains a combination of both alloploidy and ___________.
Colchicine binding to tubulin and interfering with normal chromosome segregation is an example of _______________.
Sets with similar terms
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