Are the on the same chromosome
Linked genes
Genes usually stay together
When crossing occurs,_______
Linked
Genes that are _________ do not assort independently, but may recombine by crossing over
Are located near each other on a single chromosome
Genes are linked when they
1/64
Pedram and Monica are both heterozygous for the widow’s peak trait. Individuals who have two copies of the widow’s peak allele exhibit a sharp, pointed hairline. What is the probability that the couple’s first three children will all have widow’s peaks?
Genes are carried on chromosomes
The MOST IMPORTANT reason that Mendel’s law of independent assortment is NOT universally true is that
8
How many unique haploid gametic genotypes could be produced through independent assortment by an organism with the diploid genotype AABbCCDdEe?
Identical twins
Mendel’s law of independent assortment states that the alleles at one locus separate independently of those at other loci. This law does not apply
Mendel’s law of independent assortment.
When genetically based traits are inherited independently from each other, this is known as
Appear in equal frequency in males/females and gradually replace autosomal recessive traits
Autosomal dominant traits
Occurs on the X-chromosome
In humans, X-linked traits
Darkened shapes always represent individuals w/ the trait being traced.
The following statement is True regarding pedigree analysis
100%; 50%
In pea plants, the allele for purple flower color is dominant to the allele for white flower color. If you were to perform a testcross to determine the genotype of a purple-flowered plant, you would expect the percentage of purple-flowered progeny to be _________ if the plant is homozygous and _____________ if the plant is heterozygous
makes it possible to determine the genotype of an individual of unknown genotype who exhibits the dominant version of a trait.
is a cross of an individual whose genotype for a trait is not known with an individual who is homozygous recessive for the trait.
sometimes requires the production of multiple offspring in order to reveal the genotype of an individual whose genotype is unknown
is a cross of an individual whose genotype for a trait is not known with an individual who is homozygous recessive for the trait.
sometimes requires the production of multiple offspring in order to reveal the genotype of an individual whose genotype is unknown
The testcross
0%
In certain plants, red flowers are dominant to white flowers. If a heterozygous plant is crossed with a homozygous red-flowered plant, what is the probability that the offspring will be white-flowered?
50% frequency in both the sons & the daughters
A male with an X-linked recessive disorder mates with a female who is a carrier for this same X-linked recessive disorder. Which of the following is the correct expected frequency of this disorder in their children?
50%
Gray hair in voles (H) is dominant to brown hair (h). Short claws (C) are dominant to long claws (c). What is the probability that the offspring of the cross HhCc × HHcc will have gray hair and long claws?
All of the offspring will have wrinkled seeds and a tall stem
In pea plants, tall stem length is dominant to short, and round seed shape is dominant to wrinkled seed shape. If a plant that is homozygous for tall stem and homozygous for wrinkled seeds is allowed to self-fertilize, what proportion of the offspring will have wrinkled seeds and a tall stem?
75%
A true-breeding red rose is repeatedly mated with a true-breeding white rose, and all of their offspring are red. If two of these red offspring are mated, what percentage of their offspring will be red?
The parents were both heterozygous for the gene associated with that trait
2 fruit flies are crossed, resulting in offspring w/ a 3:1 phenotypic ratio for a particular trait. This suggests….
One of the 2 plants could be homozygous for the dominant allele, while the other could be heterozygous.
How can two pea plants that have different genotypes for seed color be identical in phenotype?
Sequencing it genes
The phenotype of an organism can be best determined by
It is homozygous recessive
Albinism (lack of skin and hair pigmentation) is caused by a recessive autosomal allele. A woman and man, both normally pigmented, have an albino child together. For this trait, what is the genotype of the albino child?
The harmful allele can reside in heterozygous individuals w/ few to no negative effects.
Cystic fibrosis, which is usually lethal before reproductive ages, is a homozygous recessive disease. Why do cases continue to arise,even though people w/ the disease rarely live to reproduce?
Alleles
Most genes come in alternative forms called
Can have greater fitness than homozygous individuals.
Heterozygous individuals
No answers are correct.
Which of the following statements about dominant traits is CORRECT?
Mendel’s first law and Segregation
In genetics, the separation of alleles or homologous chromosomes during meiosis so that the haploid daughter cells have one allele or the other, but never both, is also referred to as
100%
If a true-breeding blue-flowered plant was crossed with a true-breeding white-flowered plant, what phenotypic ratio would we observe in the progeny resulting from this cross? Assume the white-flowered trait is completely dominant.
Each of 2 alleles for a given trait segregate into different gametes
The law of segregation states that
All of the flowers will be white.
In pea plants, purple flower color is dominant to white flower color. If two pea plants that are true-breeding for white flowers are crossed, in the offspring
Homozygous for the recessive allele
At locus a, the individual bearing these two homologous chromosomes is
Heterozygous individuals may pass on their copy of the disease-causing allele to offspring.
Tay-Sachs, which is a recessive lethal disease, results only when individuals possess two copies of the disease-causing allele. Which of the following statements is TRUE about this disease?
Homozygous for that gene.
A diploid individual w/ 2 identical alleles for a particular gene is said to be
Dominance
A cross b/n homozygous red-eyed flies & homozygous white-eyed flies results in progeny that all have red-eyes. This result demonstrates
Peas have a particularly long generation time.
Peas (Pisum sativum) were well suited for Mendel’s breeding experiments for all of the following reasons EXCEPT
Chromosome
Which of the following did Greg Mendel never see?
A true-breeding plant
A plant with pink flowers is allowed to self-pollinate. Generation after generation, it produces pink flowers. This is an example of
Garden Peas
Greg Mendel performed his famous experiments on
The widow’s peak hairline
This is a single-gene trait
Over 9000
Is the amount of human traits controlled by a single gene
Inherited many alleles from his father that work together to shape the baby’s nose
If a baby has “his father’s nose,” it’s because the baby has
The genotype in combination w/ the environment
Phenotypes are generally a product of
Its adverse effects can be avoided by limiting the amount of phenylalanine in the diet
Phenylketonuria is a good example of the environmental effects on phenotype because
Phelylalanine; tysorine
Phenylketonuria (PKU) is a disease characterized by the buildup of phenylalanine. The enzyme phenylalanine hydroxylase, which catalyzes the conversion of _________ to __________, is mutated and non-functional.
The inability to convert phenylalanine to tyrosine
Phenylketonuria is a genetic disorder that causes
Interaction b/n genotype & environment
The failure of a seedling to turn green if grown in the dark in an example of
It is a trait passed down to men from their mothers
Modern research on male-pattern baldness has confirmed that
44 autosomes
All genetically normal humans have
Yes, a woman can have an X-linked recessive trait if both her father has the trait and her mother is homozygous for the trait.
Yes, a woman can have an X-linked recessive trait if both her father has the trait and her mother is heterozygous for the trait.
Is it possible for a woman to have an X-linked recessive trait? If it is, how can this occur?
Often are expressed in different frequencies in males/females.
Sex-linked traits
Pleiotropic.
Most, if not all, genes are
has at least two effects: disrupting oxygen delivery and protecting against malaria.
The sickle-cell allele is considered to be pleiotropic because it
pleitropy
The impact of a single gene on more than one characteristic is called
causes fetal gonads to develop as testes shortly after fertilization.
The SRY gene
malaria
The same genetic condition that causes sickle-cell anemia can also protect against
Polygenic
This term refers to the genetic control of continuously varying traits such as height
polygenic
In the case of Mendel’s peas, a single gene determined the height of the plant; however, in humans, adult height is influenced by many genes. A trait such as human height is said to be
multiple alleles & codominance
The ABO blood type system in humans is an example of
individuals can only possess 2 alleles
Some genes, such as the human ABO blood groups, have more than two alleles. For these genes
3:4
The ABO blood type system in humans is a system that contains ________ alleles that produce __________ different phenotypes.
A, B, AB, or O
A woman with type B blood and a man with type A blood could have children with which of the following phenotypes?
OxO
This pairing indicated by letters refer to blood type phenotypes, CANNOT produce a child with type B blood
have a one-quarter chance of being a sickle-cell-free- homozygote
If two individuals who are heterozygous for the sickle-cell disease mate, their offspring will
one allele showed complete dominance over the other.
The offspring from each cross done in Mendel’s pea experiments always looked like one of the two parental varieties because
Pink
In snapdragons, flower color is inherited as a trait with incomplete dominance. There is an allele, CW, that produces no pigment, and an allele, CR, that produces red pigment. A plant with the CWCR genotype will produce _________________ flowers.
25 percent red, 50 percent pink, and 25 percent white.
Flower color in snapdragons is an example of incomplete dominance. When a red-flowered plant is crossed with a white-flowered plant, the offspring have pink flowers. If a pink-flowered plant is crossed with another pink-flowered plant, their offspring will be
incomplete dominance
A situation in which the heterozygote offspring of two homozygotes show a phenotype intermediate between those of the parents is called
white
In snapdragons, there is an allele for flower color, CW, that produces no pigment. A plant with the genotype CWCW will produce _____________ flowers.
Two affected parents have an unaffected child.
Assuming that a particular disorder is caused by an allele of a single gene, what feature of a pedigree would allow one to conclude that the disorder was caused by a dominant allele?
can skip generations
Autosomal recessive traits
