Module 2 Lab Karyotyping Flashcards
occassionally, ___ is lost or rearranged during the formation of gametes or during cell division
chromosomal
cause of chromsome being lost during formation of gametes or cell division
nondisjunction
translocation
it is estimated that one in ___ live births have some kind of chromosomal abnormality
156
some of the abnormalities associated with chromosome structure and number can be detected by a test called ___
karyotype
can show prospective parents whether they have certain abnormalities that could be passed on to their offspring
karyotypes
karyotypes can also reveal the gender of a fetus or test for certain defects through the examination of cells from ____
uterine fluid
examination of uterine fluid for karyotyping
amniocentesis
to create a karyotype, chromosomes are what
stained and photograph
homologous pairs are arranged in order by ___
size
samples for karyotyping must be
any cell undergoing mitosis
preferable cell stage for karyotping
metaphase
A chromosome whose centromere is centrally located
metacentric
Metacentric chromosomes are created because of ___, instead of longitudinal, division of the centromere during mitosis
transvers
Among human chromosomes which are classified as metacentric
1,3,16,19 and 20
are mainly characterized by the centrosome positioned off-center
submetacentric
). Pairs manifesting submetacentric formation are
2,4,5,6,7,8,9,10,11,12,17,18 and X chromosome
A type of chromosome that has its centromere near one end, producing a long arm (q arm) and a very short arm (p arm).
acrocentric
pairs of acrocentric chromosomes in humans
13, 14,15,21
A telocentric chromosome is a type of chromosome where the centromere is located at or very close to the end, resulting in only one visible arm
telocentric
is a genetic test that identifies anomalies in chromosomes, which helps in diagnosing various diseases and disorders.
karyotyping
Abnormal karyotyping results can indicate genetic syndromes like
down syndrome
klinefelter syndrome
turner syndrome
group consist of six longest chromosomes, centromeres in center
Group A
consist of four long chromosomes with centromeres away from center
B
consist of 14 medium length chromosomes with centromeres slightly off-center
C
what sex chromosomes fall in group C
x chromosomes
males have ___ C-length chromosomes while females have ___
15
16
consist of six chromosomes slightly smalelr thant the C’s with the centromeres very near to one end
group D
resembles the C group but the chromosomes are much smaller
E group
are very small with centromeres in the middle
F group
includes the four smallest chromosomes with the centromeres so close to the ends that it is difficult to see any short arms at all
group G
the male sex chromosome (Y) falls into this chromosome group
G group
therefore, a male will have ____ G-length chromosome and female will have ___ G-length chromosome
5
4
general appearance of the complete set of chromosomes in the cells of a species or an individual organism
karyotype
process by which a karyotype is discerned by determining the chromosome complement of an individual, including the number of chromosomes and any abnormalities
karyotyping
karyotyping mixes what
light microscopy and photography
karytyping usually uses microscope and photography for what phase of the cell cycle
metaphase
light microscopy and photography generally results in what for karyotyping
photomicrographic (or simply micrographic) karyogram
graphical depiction of a karyotype wherein chromosomes are generally organized in pairs, ordered by size and position of centromere for chromosomes of the same size
karyogram (idiogram)
is a laboratory technique used to study an individual’s set of chromosomes
karyotyping
purpose of karyotyping
diagnose genetic disorders
determine gender
study chromosomal abnormalities
assist in prenatal screening
by analyzing the number and structure of chromosomes, karyotyping helps identify ___ conditions
genetic
steps in karyotyping process
sample collection
cell culture
chromosome staining
analysis
what samples are most commonly sued
blood samples
cells are cultured in lab to
increase their number
___ is arrested during metaphase for optimal chromosome visibility
growth
staining highlights ___ patterns on chromosomes
banding
what stains are used in chromosome staining
giemsa stain
types of chromosomal banding
g banding
q banding
r banding
cbanding
refers to alternating light and dark regions along the length of a chromosome, produced after staining with a dye.
chromosome banding
humans have ___ chromosomes arranged in __ pairs
46
23
22 pairs are called ___
autosomes
each chromosome has a unique ___ pattern
banding
group A
subgroup or subclass
size
relative position of chromosomes
1-3
large
metacentric
group B
subgroup or subclass
size
relative position of chromosomes
4-5
large
submetacentric
group C
subgroup or subclass
size
relative position of chromosomes
6-12, X
medium
submetacentric
group D
subgroup or subclass
size
relative position of chromosomes
13-15
medium
acrocentric
group E
subgroup or subclass
size
relative position of chromosomes
16-18
relatively short
submetacentric
group F
subgroup or subclass
size
relative position of chromosomes
19-20
short
metacentric or submetacentric
group G
subgroup or subclass
size
relative position of chromosomes
21-22, Y
short
acrocentric
extra copy of chromosome 21 (trisomy 21)
down syndrome
most common chromosomal disorder
down syndrome (Trisomy 21)
genetic condition includes intellectual disability, distinct facial features, heart defects
trisomy 21 (down syndrome)
what does the extra chromosome in trisomy 21 do
causes mental and physical developmental delays
missing or incomplete X chromosome in females
turner syndrom
genetic condition affects 1 in 2,5000 female births
turner snydrome
characteristic of genetic condition include short stature, infertility, heart and kidney failure
turner syndrome
extra x chromosome in males (XXY)
klinefelter syndrome
genetic condition affecting 1 in 500 to 1,000 male births
klinefelter syndrome
genetic characteristics that has a reduced testosterone, breast development, and learning disabilities
klinefelter syndrome
when interpreting karyotypes, one shoud:
identify abnornalities (look for extra or missing chromosomes, check for structural changes like deletions or duplications)
look for common abnormalities
trisomies (e.g. down syndrome)
monosomies (e.g. turner syndrome)
importance of accurate interpretation (accurate diagnosis guides treatment and management, help in genetic counseling and family planning)
tools and techniques (use of specialized software for analysis, consultation with genetcisist for complex cases)
real-world applications for karyotyping that is used for genetic disorders in fetuses
prenatal screening
real-world applications for karyotyping that helps identify chromosomal abnormalities in cancer cells
cancer research
real-world applications for karyotyping that assist in diagnosing chromosomal causes of infertility
fertility treatments
what samples can be used for karyotyping?
Blood cells
Bone marrow cells
Amniotic fluid cells
Chorionic Villus Cells
Skin or tissue biopsies
Tumor cells
what can karyotyping be used for
Diagnosing genetic disorders
Detecting chromosomal changes in cancer
Prenatal diagnosis
Infertility and recurrent miscarriages
Monitoring treatment response
how can karyotyping be used to determine evolutionary relationships
Comparative Chromosome Analysis
Identifying Chromosomal Rearrangements
Tracing Ancestral Chromosomes
what are some examples of disorders that can be identified by karyotyping
Down syndrome (Trisomy 21): Caused by an extra copy of chromosome 21, leading to developmental delays and physical characteristics.
Turner syndrome: Affects females with a missing or partially missing X chromosome, resulting in short stature and infertility.
Klinefelter syndrome (XXY): Males have an extra X chromosome, which can lead to reduced fertility and development of secondary sexual characteristics.
Patau syndrome (Trisomy 13): Characterized by severe intellectual disability and physical abnormalities due to an extra copy of chromosome 13.
Edwards syndrome (Trisomy 18): Leads to severe developmental delays and physical malformations due to an extra copy of chromosome 18.
Cri-du-chat syndrome: Caused by a deletion on chromosome 5, resulting in intellectual disability and a characteristic high-pitched cry.
how can karyotypign be used for pregnancy
Prenatal Screening: Karyotyping is performed as part of prenatal screening tests to detect chromosomal abnormalities such as Down syndrome, Edwards syndrome, and Patau syndrome.
Amniocentesis: This procedure involves collecting a small sample of amniotic fluid from the uterus. The fluid contains fetal cells, which are cultured and analyzed for chromosomal abnormalities through karyotyping. Amniocentesis is typically done between the 15th and 20th weeks of pregnancy.
Chorionic Villus Sampling (CVS): In CVS, a small sample of cells from the placenta is collected either through the cervix or the abdominal wall. These cells are then karyotyped to detect chromosomal abnormalities. CVS is usually performed between the 10th and 13th weeks of pregnancy.
how can karyotyping be used for stem cell therapies
Genetic Stability Monitoring: Karyotyping is used to monitor the genetic stability of stem cell lines, including human embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), and mesenchymal stem cells (MSCs). This helps in detecting chromosomal abnormalities that may arise during cell culture and expansion.
Quality Control: Before stem cells are used for therapeutic purposes, karyotyping is performed to ensure that the cells have a normal chromosomal complement. This is essential to prevent the introduction of genetic abnormalities into patients.
Preventing Tumorigenicity: Long-term culture of stem cells can lead to chromosomal abnormalities, which may increase the risk of tumorigenicity (formation of tumors). Regular karyotyping helps in identifying and eliminating such abnormal cells, ensuring the safety of stem cell therapies
what are limitations of karyotyping
Resolution: Karyotyping has a limited resolution and can only detect large chromosomal abnormalities (usually greater than 5 megabases). Smaller genetic changes, such as point mutations or small deletions/insertions, cannot be detected.
Time-Consuming: The process of culturing cells, preparing samples, and analyzing karyotypes can be time-consuming, taking several days to weeks.
Labor-Intensive: Karyotyping requires skilled technicians and involves meticulous preparation and analysis of chromosomes under a microscope.
Cannot Identify Single-Gene Disorders: Karyotyping is not suitable for detecting single-gene disorders or subtle genetic changes, which require more specialized genetic testing techniques like DNA sequencing.
Interpreting Variability: Some chromosomal variations may be of uncertain significance, making it challenging to interpret the results accurately.
Requires Dividing Cells: Karyotyping relies on cells that are actively dividing (usually in the metaphase stage). This can limit the types of samples that can be used and may require cell culture, which adds complexity and time to the process.
