SCI1000 Module 6
An individual is born to one normal parent and one parent who is heterozygous for an autosomal dominant disorder. Based on your understanding of inheritance patterns, what is the likelihood that this individual inherited the disorder? (Hint: Draw a hypothetical Punnett square to help visualize the problem.)
1/2 (50%)
About how many genes does the X chromosome carry?
1000
If a biological mother was a carrier for a recessive X-linked trait but the biological father did not, how many sons and daughters would express the recessive trait?
50% of sons and 0% of daughters
About how many genes does the Y chromosome carry?
60
In humans, what are autosomes?
Autosomes are the 22 chromosomes that are not involved in sex determination.
How is a Y-linked trait inherited?
From biological father to son
What is the Barr body?
In female cells, one of the X chromosomes becomes inactivated.
What does that SRY gene do?
It activates genes important for producing the cells of the testes.
How does gene dosage impact the cell?
It impacts the amount of gene product in the cell.
How are sex chromosomes different from autosomes?
They are involved in sex determination.
An individual has a genotype of IBi. What is their blood type?
Type B
Most sex-linked traits are found on which chromosome?
X chromosome
Pedigrees differ from family trees in that they track what within a family? Choose the best answer.
a specific trait or traits
If a mother was homozygous for a dominant X-linked trait, how many of her sons and daughters would have the trait?
all her offspring would have the trait
Under what circumstance is the Rh factor of most concern for blood compatibility?
an Rh- mother pregnant with her second Rh+ baby
Having an abnormal number of chromosomes is called what?
aneuploidy
If an individual has a genotype of IAi, what antibodies would you expect to see in their blood?
anit-B antibodies
If a pedigree is trying to determine the genetic status of a specific individual with regards to the trait of interest, how are they referred to?
as the proband
The ABO system of blood type refers to what?
carbohydrate surface markers on the red blood cell
What is the term for a chromosomal structural anomaly in which a large portion of one chromosome has broken off and reattached to another chromosome?
chromosomal translocation
In a pedigree, what shape represents a female?
circle
An individual heterozygous for the IA and IB alleles has a blood type of AB. What type of inheritance pattern is this?
codominance
In human genetics, what are alleles? Choose the best answer.
different versions of the same gene
What term do we used to describe the fact that humans have two copies of every autosome and one pair of sex chromosomes?
diploid
What inheritance pattern does the Rh factor follow?
dominant/recessive
What is the unit of heredity in humans?
gene
What is the term used to describe the number of times a gene appears in the genome?
gene dosage
Having the correct gene dosage is important for the overall ___________ of the cell and organism.
health and balance
What makes different blood types incompatible with each other?
incompatible antibodies and surface antigens on the red blood cells
An individual inherits one allele for curly hair from their mother and one allele for straight hair from their father. The individual expresses wavy hair. What type of inheritance pattern is this?
incomplete dominance
In a pedigree, what do square symbols represent?
males
In a pedigree, what is indicated when a square and a circle are connected by a horizontal line?
married/mated pair
If the development of a disease is affected by both genetic and environmental factors, what type of inheritance pattern does it have?
multifactorial
What is the term used to describe those traits that are not only influenced by genes but also by environmental factors?
multifactorial traits
Even though individuals only have two alleles for any given gene, there may be many different alleles for that gene within the human population. What is the term for this phenomenon?
multiple alleles
The presence of three different alleles for the ABO blood typing system (IA, IB, and i) is an example of what?
multiple alleles in the population
If an X-linked trait is recessive, and only the biological father (not the mother) has an allele for the recessive trait, will any of the offspring have the trait?
no
Trisomy refers to what?
one extra copy of a chromosome
What is the term used to describe genetic traits that are produced by the interaction of two or more different genes?
polygenic traits
What aspects of the blood are responsible for different blood types?
protein and carbohydrate markers on the cells
The markers on the surface of which blood cells are being considered when discussing blood type?
red blood cells
What allows complex family information to be condensed and easily read in a pedigree? Choose the best answer.
standardized symbols and relationship connections
What term refers to the disruption of the normal physical configuration of a chromosome? Choose the best response.
structural anomalies
If a chromosome is seen to have two centromeres, what kind of chromosomal abnormality is this?
structural anomaly
What is the most important Y-linked trait?
the SRY gene
Aneuploidy in which chromosomes is most likely to be survived?
the smaller chromosomes
How do most chromosomal disorders arise?
through de novo mutation in one of the biological parent's gametes
How does aneuploidy most often occur?
through non-disjunction at meiosis of one of the gametes
How have we gained most of our understanding of human genetics? Choose the best answer.
through studying genetics in sexually reproducing model organisms such as mice and fruit flies
In a pedigree, what are Arabic numerals used for?
to identify individuals within a generation
In a pedigree, what are Roman numerals used for?
to number the generations
