final pt 3 Flashcards
A shotgun sequencing project yields the following sequence for a strand of DNA.
All of the sequences overlap with the sequence above.
All of the genetic material transferred from a parent to an offspring is known as a:
genome
Genome sequencing includes the following steps:
- putting the sequences in the correct order
- matching regions of overlap
- breaking the DNA into small fragments
- reconstructing the long sequence of nucleotides
- sequencing the DNA
In what order are these steps carried out?
3-5-2-1-4
Which of the following would be found in DNA sequences but not in mRNA sequences?
transcription start sites
Which one of the following types of sequences can be found in a genome?
All of these choices are correct.
Deletions that eliminate a multiple of three nucleotides can:
delete amino acids in a polypeptide chain.
The number of new mutations in organisms following a round of genome replication:
generally increases with larger genomes.
Insertions and deletions of single nucleotides:
cause frameshift mutations.
A population of mosquitoes is exposed to the pesticide DDT for several generations. At the end of that time, most individuals in the population are resistant to DDT. The most likely reason is that
Some individuals in the original population had the mutations that led to resistance
_____ mutations are important to the evolutionary process; most cancers result from _____ mutations.
Germ-line; somatic
An individual is heterozygous for a gene if:
he or she developed from a sperm and egg that carried different alleles.
In a population of organisms with 4 alleles, how many homozygous genotypes are possible? How many heterozygous genotypes are possible?
4; 6
The term “genotype-by-environment interaction” applies to a situation in which:
the effects of genotype and environment on a phenotype are interdependent.
Which of the following types of mutations are thought to be the least common?
beneficial mutations
“Any difference among individuals that is sufficiently common such that it would almost certainly be present in a group of 50 individuals chosen at random” is the definition of a(n):
polymorphism
Mendel studies seven different traits in the garden pea. What genetic term is used to describe an observable trait, such as those studied by Mendel?
phenotype
A sexually reproducing animal has two unlinked genes, one for head shape (H) and one for tail length (T). Its genotype is HhTt. Which of the following genotypes is possible in a gamete from this organism?
HT
Different ratios occur in crosses with single gene pairs or two gene pairs. What types of ratios are likely to occur in crosses dealing with a single gene pair?
3:1, 1:1, 1:2:1
Mendel’s observation of the segregation of alleles in gamete formation has its basis in which of the following phases of cell division?
anaphase I of meiosis
Feather color in birds of paradise is determined by two different genes, Y and B, one for pigment on the outside and one for the inside of the feather. YYBB, YyBB, or YYBb is green; yyBB or yyBb is blue; YYbb or Yybb is yellow; and yybb is white. A blue budgie is crossed with a white budgie. Which of the following results is NOT possible?
green and yellow offspring
Given equal probabilities of the birth of a boy or girl, if a group of four siblings consists of all girls, what is the probability that the next birth is a boy?
1/2
Genes located along the X chromosome:
are called X-linked genes
Which one of the following statements regarding the human Y chromosome is true?
The Y chromosome contains approximately 50 genes
The pedigree shown here pertains to a trait due to a rare, X-linked recessive mutation.
Individual 1 has an affected brother, but the genotypes and phenotypes of individuals 1–4 are unknown. What is the probability that individual 1 is heterozygous? What is the probability that individual 3 is heterozygous? What is the probability that individual 4 is affected?
1/2; 1/4; 1/4
Red-green color blindness is due to a mutant gene in the X chromosome. An XX female with normal color vision and an XY male with normal color vision have a child with karyotype XXY who is color blind. The likely explanation is:
the mother was heterozygous for the color-blind mutation
A key difference between single-gene traits such as those Mendel studied and complex traits such as human height is that:
single-gene traits are generally uninfluenced by the environment, whereas complex traits have a significant environmental component.
If all variation among individuals in a population is due to differing environments, heritability is ____, and the slope of the line used to measure it is ____.
0; 0
Which of the following would be good examples of genotype-by-environment interactions?
a strain of corn whose yield varies with the amount of nutrients in the soil
Which of the following is the best example of how we can separate the effects of genes and the environment on the expression of a complex trait?
In a group of individuals of the same sex, about 80% of the variation in height among individuals is due to genetic differences and 20% is due to environmental differences.
If all variation among individuals in a population is due to differing genotypes, heritability is ____, and the slope of the line used to measure it is ____.
100%; 1
Cancer is usually due to:
a series of mutations that occur in a single lineage of somatic cells.
You are studying two traits in fruit flies:
eye color where there are two colors, brown and red, and
wing shape where there are straight and curled phenotypes.
You mate two flies that are heterozygous for the genes that control both of these traits and get the following phenotypes in the following ratio:
9 red and straight; 3 red and curled; 3 brown and straight; 1 brown and curled
Considering the traits in the previous question, which alleles separated at which stages of meiosis?
red segregated from brown in meiosis I, and straight segregated from curled in meiosis I
In humans, mitochondria (and their genomes) show:
strict maternal inheritance
