PCB 3063 EXAM 2 QUESTIONS & ANSWERS
genetics? - answers :advantages:
• there have already been extensive studies on our anatomy and biochemistry
• detailed pedigree records
Disadvantages:
• ethical and cultural limitations (ex. Controlled matings)
• long generation time
• often do not have many offspring
Autosomal dominant traits - answers :inheritance pattern of a dominant allele on an
autosome. The trait appears equally in males and females, and a person with the trait
has at least one parent with the trait. The trait does not skip generations, but is usually
rare (most people with it are heterozygotes).
Autosomal recessive traits - answers :traits that are only displayed if one has two copies
of the recessive allele on an autosome. These traits appear with equal frequency in
males and females, but tend to skip generations and are more likely to occur with
consanguinity
Consanguinity - answers :mating between closely related individuals
X-linked recessive traits - answers :occur more often in males, since they only need one
copy of the recessive gene for the trait to show, while females will need it on both x
chromosomes. They tend to skip generations as the progeny and genotype of the
mother alternates (they are only inherited from the mother's x).
X-linked dominant traits - answers :these are more common in females, as the x can be
inherited from either parent; if a son gets it, it was inherited from the mother. Women
who are affected are often heterozygous, and it does not skip generations.
Y-linked traits - answers :traits that only affect males, are only inherited by the father,
and affect all sons of an affected father. It does not skip generations
Ultrasound prenatal genetic testing - answers :prominent genetic disorders can be
detected, as well as fetal size
Fetal karyotyping - answers :an analysis of fetal chromosomes during metaphase for
visible abnormalities by looking at fetal cells
Amniocentesis - answers :a type of prenatal genetic testing in which amniotic fluid is
obtained, then used to grow fetal cells in cultures. They are then analyzed to detect
certain genetic and congenital defects through karyotyping, and is not very risky.
, Chronic villus sampling - answers :sampling of placental tissues for prenatal diagnosis
of potential genetic defects, but is riskier than amniocentesis (1:100 result in
miscarriage)
Maternal blood tests - answers :looks for alpha fetoprotein in the mother's blood (which
resulted from the fetus) for genetic testing.
Fetal cell sorting - answers :separation of fetal cells from maternal blood using facs
(fluorescence activated cell sorting), then analyzing it through karyotyping or dna testing
Preimplantation genetic diagnosis - answers :is a technique used to identify genetic
defects in embryos created through in vitro fertilization (ivf) before transferring them into
the uterus. The zygote is able to divide under laboratory conditions, then removed at the
8-16 cell stage for analysis
- ethically controversial because it can be used to select genes once certain ones have
been identified
Postnatal genetic testing - answers :newborn screening for genetic defects, in which
early intervention is implemented
Heterozygote screening - answers :tests members of a population to identify
heterozygous carriers of a disease-causing allele who are healthy but have the potential
to produce children who have the disease.
Pre-symptomatic testing - answers :a genetic test performed on a person who has a
family history but no symptoms of a specific disease at the time of testing, to determine
whether or not the mutation for that disorder has been inherited. It is especially useful
for traits with a late onset for symptoms (ex. Huntington's).
Foxp2 - answers :a gene that is important in language and speech production and is
believed to be an evolutionary step towards speech from other primates
When two genes that control a different trait are located on different chromosomes,
what percent of gametes have new combinations of alleles? - answers :50%
Recombinant genes - answers :genes that are made through crossing over between
homologs during prophase i and independent assortment
Linked genes - answers :genes that are physically to one another on the same
chromosome and tend to be inherited together. If inherited, they are the same alleles as
the parent
Linkage group - answers :alleles of different genes that are located on the same
chromosome and tend to be inherited together
genetics? - answers :advantages:
• there have already been extensive studies on our anatomy and biochemistry
• detailed pedigree records
Disadvantages:
• ethical and cultural limitations (ex. Controlled matings)
• long generation time
• often do not have many offspring
Autosomal dominant traits - answers :inheritance pattern of a dominant allele on an
autosome. The trait appears equally in males and females, and a person with the trait
has at least one parent with the trait. The trait does not skip generations, but is usually
rare (most people with it are heterozygotes).
Autosomal recessive traits - answers :traits that are only displayed if one has two copies
of the recessive allele on an autosome. These traits appear with equal frequency in
males and females, but tend to skip generations and are more likely to occur with
consanguinity
Consanguinity - answers :mating between closely related individuals
X-linked recessive traits - answers :occur more often in males, since they only need one
copy of the recessive gene for the trait to show, while females will need it on both x
chromosomes. They tend to skip generations as the progeny and genotype of the
mother alternates (they are only inherited from the mother's x).
X-linked dominant traits - answers :these are more common in females, as the x can be
inherited from either parent; if a son gets it, it was inherited from the mother. Women
who are affected are often heterozygous, and it does not skip generations.
Y-linked traits - answers :traits that only affect males, are only inherited by the father,
and affect all sons of an affected father. It does not skip generations
Ultrasound prenatal genetic testing - answers :prominent genetic disorders can be
detected, as well as fetal size
Fetal karyotyping - answers :an analysis of fetal chromosomes during metaphase for
visible abnormalities by looking at fetal cells
Amniocentesis - answers :a type of prenatal genetic testing in which amniotic fluid is
obtained, then used to grow fetal cells in cultures. They are then analyzed to detect
certain genetic and congenital defects through karyotyping, and is not very risky.
, Chronic villus sampling - answers :sampling of placental tissues for prenatal diagnosis
of potential genetic defects, but is riskier than amniocentesis (1:100 result in
miscarriage)
Maternal blood tests - answers :looks for alpha fetoprotein in the mother's blood (which
resulted from the fetus) for genetic testing.
Fetal cell sorting - answers :separation of fetal cells from maternal blood using facs
(fluorescence activated cell sorting), then analyzing it through karyotyping or dna testing
Preimplantation genetic diagnosis - answers :is a technique used to identify genetic
defects in embryos created through in vitro fertilization (ivf) before transferring them into
the uterus. The zygote is able to divide under laboratory conditions, then removed at the
8-16 cell stage for analysis
- ethically controversial because it can be used to select genes once certain ones have
been identified
Postnatal genetic testing - answers :newborn screening for genetic defects, in which
early intervention is implemented
Heterozygote screening - answers :tests members of a population to identify
heterozygous carriers of a disease-causing allele who are healthy but have the potential
to produce children who have the disease.
Pre-symptomatic testing - answers :a genetic test performed on a person who has a
family history but no symptoms of a specific disease at the time of testing, to determine
whether or not the mutation for that disorder has been inherited. It is especially useful
for traits with a late onset for symptoms (ex. Huntington's).
Foxp2 - answers :a gene that is important in language and speech production and is
believed to be an evolutionary step towards speech from other primates
When two genes that control a different trait are located on different chromosomes,
what percent of gametes have new combinations of alleles? - answers :50%
Recombinant genes - answers :genes that are made through crossing over between
homologs during prophase i and independent assortment
Linked genes - answers :genes that are physically to one another on the same
chromosome and tend to be inherited together. If inherited, they are the same alleles as
the parent
Linkage group - answers :alleles of different genes that are located on the same
chromosome and tend to be inherited together
