Genetics Exam 2 - Quiz Flashcards
calculate the narrow sense heritability for a grandparent-grandchild relationship with the observed correlation coefficient is 0.2
0.8
inbreeding reduces which of the following variances to near 0
genetic variance
what must be true regarding the strains of organisms used to construct a QTL map
they must differ for the quantitative trait AND the molecular markers
QTL mapping determines the relationship between genes for quantitative traits and which of the following
molecular markers such as RFLP’s
quantitative traits usually have which of the following characteristics
continuous distribution, polygenic basis, environmental infleunce
A selective breeding program is trying to develop an agricultural plant with decreased stem length to aid in mechanical harvesting. The mean stem height of the population is 36 cm while the mean stem height of the parents is 30 cm and the mean stem height of the offspring is 33 cm. What is the realized heritability for stem height in this crop?
0.5
What must be true for a correlation coefficient to be calculated between two traits?
The values for the traits must have been obtained from unbiased sampling.
The traits must follow a normal distribution.
The relationship between the two traits must be linear.
Which of the following best describes the degrees of freedom for the calculation of variance?
n-1
The square root of the variance is called the _____.
standard deviation
When analyzing two variables, the strength of the association between the variables is called the ____.
correlation coefficient
The term for a group of individuals from the same species that can interbreed with one another is
population
In the equation p2 + 2pq + q2 = 1, what does the term 2pq represent?
heterozygous
Given a population of 1,000 individuals what is the average number of generations it will take to fix a new mutation assuming no selection for or against the new mutation?
4000
What is the probability of fixation of a gene in a population of 30 individuals (assume no selection for or against a mutation)?
1.67%
What is the frequency of an allele in a conglomerate population if 50 individuals from a population where the allele has a frequency of 0.6 migrates into a population of 450 individuals where the allele frequency is 0.3?
0.33
Natural selection occurs when
individuals whose phenotypes are best suited for environmental conditions have higher reproductive success and contribute more alleles to the next generation.
The prevalence of the allele for sickle cell anemia in some populations is an example of which of the following?
balancing selection
The probability that two alleles will be identical for a given gene in an individual because the alleles are from the same ancestor is estimated by
the inbreeding coefficient.
Microevolution is defined as
changes in the gene pool from one generation to the next.
You are preparing to perform DNA fingerprinting by PCR for the first time. Select the reagent that would result in complications in the interpretation of your results.
PCR primers that anneal to the repetitive region of the microsatellites
In a mapping experiment with three genes, which phenotype should occur most often in the F2 offspring?
parental phenotypes
Which of the following are necessary characteristics of an organism in order to easily construct a genetic linkage map?
short generation times
produces large numbers of offspring
easily crossed
A Xw+m+Xwm female was mated to a XwmY male. Out of 1000 total F1 progeny there were 230 flies that were otherwise wild type with white eyes and 240 flies that were otherwise wild type with miniature wings. What is the distance between the genes for eye color and wing length?
47 map units
Twin spotting provides evidence of what genetic event?
mitotic recombination
Another name for a chromosome is a _______, since it contains genes that are often inherited together.
linkage group
The first observational evidence that genes may be inherited together rather than by simple Mendelian inheritance was provided by _____.
bateson and punnett
The diploid garden pea plant has 14 chromosomes. The haploid fungus Neurospora crassa has 7 chromosomes. Neither organism has separate male and female individuals. Which of the following correctly identifies the number of linkage groups in each organism?
Garden pea has 7 linkage groups, and Neurospora has 7.
Creighton and McClintock worked with _____ as their model system to show that homologous chromosomes physically exchange genetic information during crossing over.
corn
In a chi square test to determine if two genes are linked or assorting independently, what is the default (null) hypothesis that is tested?
The genes are assorting independently.
The individual who is credited with discovering genetic linkage in Drosophila is _____.
Thomas Hunt Morgan
Which of the following expressions denotes a trisomic organism?
2n+`
A _______ translocation occurs when a piece of one chromosome is attached to another chromosome.
simple
Given the following sequence of genes on a chromosome, determine what change in chromosome structure occurred. The asterisk (*) indicates the centromere.
Before: A B C D * E F G H
After: A B C D * E F E F G H
gene duplication
Inversions detectable by light microscopy are contained within what percent of the human population?
approximately 2%
Which of the following would produce the most euploid progeny, sperm cells that result from a nondisjunction following meiosis I or meiosis II?
Sperm that are produced following a non-disjunction event in meiosis II.
The African clawed frog (Xenopus laevis) is an allotetraploid, likely as a result of an interspecies mating long ago, followed by a duplication of the entire genome. Xenopus laevis is fertile and has a normal life cycle. In contrast, mules, the allodiploid offspring of a male donkey and a female horse, are generally sterile. Why can Xenopus reproduce and mules cannot?
In allotetraploid organisms each chromosome has a chromosome to pair up with in meiosis, whereas in allodiploid organisms they do not.
Which correctly describes mitotic nondisjunction?
relatively rare event
results in loss of chromosomes in some cells
it usually does not affect all of the cells of the organism
The term _______ refers to genetic differences between members of the same species.
genetic variation
Edward and Patau syndromes are examples of __________.
aneuoploidy
Describe endopolyploidy, and how it might benefit an organism.
Portions of the organism have extra copies of all chromosomes, for producing additional gene products.
In the experiment performed by Lederberg and Tatum bacteria of different genotypes had to be mixed together to obtain a genetic transfer. However, Davis performed the experiment in a slightly different manner by separating cells with a filter incapable of allowing bacteria to pass. What possibility did the experiment by Davis exclude that could have occurred by the protocol used by Lederberg and Tatum?
transformation
The site on a plasmid that is cut, producing a single strand of DNA, to allow conjugation to occur is called the ____________.
origin of transfer
DNA transfer by transduction depends on what occasional mistake that can occur during a phage lytic cycle?
A piece of host cell DNA is packaged into a phage.
Who was the first to discover the process of natural transformation?
Griffith
What do competence factors do?
allow DNA in the environment to bind to the cell surface
If the origin of transfer was located directly to the right of the galE gene on this map of the E. coli chromosome, and gene transfer proceeded counterclockwise, how many minutes after the galE gene was transferred would the dnaB gene be transferred in an interrupted mating experiment?
25min
How do researchers interrupt the process of conjugation?
using a blender
What is the most important result of horizontal gene transfer as it relates to human health?
It spreads antibiotic resistance in pathogenic bacteria.
DNA transfer via a physical connection between two bacteria is known as
conjugation
Which does not require any recombination with the bacterial chromosome?
conjugation
