Exam 2 Flashcards
TDF
Testis Determining Factor
XX SRY+
-Male External Characteristics
-Shorter than average
-Small testes
-Infertile = Lack AZF gene (sperm production gene)
-Usually male gender identity
-May need additional testosterone at puberty
Swyer Syndrome
- XY SRY-
-Female external sex characteristics
-Usually female gender identity
Uterus and fallopian tubes develop normally
-Hormone supplementation required for proper breast development and uterine growth
-Gonads are undeveloped clumps of tissue
-can only become pregnant via a donated egg or embryo
What transcription factor is believed to behave as the master switch for controlling the genes involved in sexual differentiation?
TDF
Androgen Insensitivity Syndrome (AIS)
-XY AR-
- Mutant AR gene
-the androgen receptors don’t work properly and the cells are less responsive to testosterone
What does Complete AIS result in?
-Female external characteristics
-Usually female identity
-No uterus = infertile
-Undescended testes located in the pelvis or abdomen
What is the notation used when a female is the heterogametic sex?
Male = ZW
Female = ZZ
What is the process of G-banding?
-Colchine arrests cells in metaphase
-Then treaed with trypsin
-Lastly, Giemsa stained
Karyotype
Ordered array of the chromosomal complement of a cell
How are chromosomes arranged in a karyotype?
-Distinguished by size
-Centromere position
-Banding pattern
Arranged largest to smallest
Aneuploidy
Individual chromosomes are either missing, or present extra copies
Klinefelter Syndrome
-XXY
-Tall with long arms and legs with large feet and hands
-Testes are rudimentary and fail to produce sperm
-Slight breast enlargement and hips often rounded
-Intelligence below normal range
Turner Syndrome
-X
-Female external genitalia and internal ducts
-Ovaries are rudimentary
-Normal intelligence
-Short stature
-Flat underdeveloped breasts
-Broad, shieldlike chest
Triplo-XXX
-47,XXX
-Three X chromosomes along with a normal set of autosomes
-Female phenotype
-1/1000 live births
-Mild symptoms: taller than average and sometimes a slight learning delay
XYY Condition
-Males over 6 feet tall
-Subnormal Intelligence
-Some evidence of predisposition to violence
Lyon Hypothesis
-Mary A. Lyon, 1925-2014
-Inactivation and creation of Barr body is random and all descendant cells have same inactivation
What hypothesis best explains the fur color in calico and tortoiseshell cats?
Lyon Hypothesis
What is the mechanism of action for the inactivation of an X chromosome?
-X-inactive specific transcript (XIST) gene
-Located in end of X chromosome p arm in humans
-Critical to X inactivation
-only expressed on inactivated X chromosome
Euploidy
-Describes a cell that has an exact multiple of the haploid number (n) of chromosomes
Monosomy
2n-1
-loss of one member of a homologous pair
Disomy
2n
Trisomy
2n+1
-Gain of one chromosome, resulting in three homologous chromosomes
tetrasomy
2n+2
-Gain of two homologous chromosomes, resulting in four homologous chromosomes
Diploidy
2n
Triploidy
3n
tetraploidy
4n
Trisomy 21
-Down Syndrome
-Low muscle tone
-Small stature
-Upward slant to the eyes
-A single deep crease across the center of the palm
-Intellectual disability
Polyploidy
Addition of entire chromosome sets
Allopolyploidy
Polyploidy in which extra chromosome sets are derived from two or more species
Autopolyploidy
Polyploid in which extra chromosome sets are derived from the same species
Nullisomy
Loss of both members of a homologous pair
Chromosome Rearrangement
Change in chromosome structure
Chromosome Duplication
Duplication of chromosome segment
Chromosome Deletion
Deletion of a chromosome segment
Chromosome Deletion
Deletion of a chromosome segment
Inversion
Chromosome segment inverted 180 degrees
Paracentric Inversion
Inversion that does not include the centromere in the inverted region
Pericentric inversion
Inversion that includes the centromere as part of the inverted region
Translocation
Movement of a chromosome segment to a nonhomologous chromosome or to another region of the same chromosome
Nonreciprocal Translocation
Movement of a chromosome segment to a nonhomologous chromosome or to another region of the same chromosome without reciprocal exchange
Reciprocal Translocation
Exchange between segments of nonhomologous chromosomes or between regions of the same chromosome
Aneuploidy
Change in the number of individual chromosomes
Amphidiploid
A hybrid between two species that has a complete diploid chromosome set from each parent species
-It’s fertile
What must occur in order for an amphidiploid organism to be born?
Nondisjunction at an early mitotic cell division
Wheat X Rye =
Titicale
-Wheat = high protein, high yield grain
-Rye = versatility of growth in unfavorable conditions
Radish X Cabbage =
Rabbage
Plum X Apricot =
Pluot
Less than 55 repeats of CGG =
Person is typical
55 to 230 repeats of CGG =
Person is “carrier”
More than 230 repeats of CGG =
person has fragile x
What cause fragile X?
When a person has more than 230 repeats of CGG, the gene becomes methylated and when that happen no mRNA can be produced. (gene inactivation)
Duplication of chromosome 4’s short arm =
-Small head
-Short neck
-Low hairline
-Reduced growth
-Intellectual disability
Duplication of chromosome 4’s long arm =
-Small head
-Sloping forehead
-Hand abnormalities
Duplication of chromosome 7’s long arm =
-Delayed development
-Asymmetry of the head
-Fuzzy scalp
-Small nose
-Low-set ears
Duplication of chromosome 9’s short arm =
-Characteristic face
-Variable intellectual disability
-High and broad forehead
-Hand abnormalities
Deletion of chromosome 5’s short arm =
Cri-du-chat Syndrome
-Small head
-Distinctive cry
-Widely spaced eyes
-Round face
-Intellectual disability
Deletion of chromosome 4’s short arm =
Wolf-Hirschhorn Syndrome
-Small head with high forehead
-Wide nose
-Cleft lip and palate
-Sever intellectual disability
Deletion of chromosome 4’s long arm =
-Small head
-Mid to moderate intellectual disability
-Cleft lip and palate,
-Hand and foot abnormalities
Deletion of chromosome 7’s long arm =
Williams-Beuren Syndrome
-Facial features
-Heart defects
-Mental impairment
Deletion of chromosome 15’s long arm =
Prader-Willi Syndrome
-Feeding difficulty at early age but becoming obese after 1 year of age
-Mild to moderate intellectual disability
Deletion of chromosome 18’s short arm =
-Round face
-Large low-set ears
-Mid to moderate intellectual disability
Deletion of chromosome 18’s long arm =
- Distinctive mouth shape
-Small hands
-Small head
-Intellectual disability
What are some common polyploid plants?
-Seedless watermelon (3n)
-Banana (3n)
-Blackberries (4n)
-Peanuts (4n)
-Sweet potato (5n)
-Wheat (5n)
Strawberry (8n)
Is polyploidy more common in plant or in animals?
Plants
What is unique about Ambystoma salamanders?
They “steal” sperm from co-occurring species, resulting in numerous polyploid genome combinations
What are the four major characteristics required for a molecule to be considered genetic material?
VERS
-Variation (by mutation)
-Expression (of information)
-Replication (to pass on to the next generation)
-Storage (of information)
What is genetic material?
It is the source o variation among organisms through process of mutation.
Mutation in DNA
Is reflected in transcription and translation affecting a specific protein.
Genetic Variation
provides raw material for process of evolution
What observations favored protein as the genetic material?
-1910 - Pheobus Levine’s tetranucleotide hypothesis
-Proteins are diverse and abundant
What experiment was performed by Griffith?
He looked at a virulent strain of heat treated Streptococcus pneumoniae mixed with a non virulent strain that wasn’t heat treated and it killed the mouse.
What experiment was performed by Avery, MacLeod, and McCarty?
Treated heat killed IIIs (The virulent strain) and treated it with RNase, Protease, and DNase.
What experiment was done by Hershey and Chase?
Tagged protein of a bacteriophage with 35S and tagged other bacteriophage’s DNA with 32P. These bacteriophage were used to infect bacteria and then look at the progeny phage to see if they had the radioactive isotope.
How does DNA relate to classical genetics/ Mendelian genetics?
It is indirect evidence
Did the renown Linus Pauling know the correct molecule (aka not protein secondary structure)?
No
Who came up with the structure of DNA?
Watson and Crick utilizing data from Wilkins, Franklin, Chargaff, and others.
What is Franklin famous for?
X-ray diffraction of DNA molecules that contributed to the Watson and Crick discovering the structure of DNA.
How does ribose differ from deoxyribose?
Ribose has an extra O atom the deoxyribose doesn’t have on the 2’ carbon.
Who discovered the base composition of DNA?
E. Chargaff
What was Chargaff’s experiment?
1- Extract Chromosomal Material
2- Remove the Protein
3- Hydrolyze the DNA to release the bases from the DNA strands
4-Separate the bases by chromatography
5- Extracted Bands from paper into solution and measure by Spectrophotometer (absorption)
6- Compare the base content in the DNA from different organisms
Nomenclature for just a nitrogenous base?
-Adenine
-Guanine
-Cytosine
-Thymine
-Uracil
Nomenclature for a nucleoside or nucleotide N base?
-Adenosine
-Guanosine
-Cytidine
-Thymidine
-Uridine
What is the structural difference between pyrimidines and purine?
Purines have a 6 member ring and a five member ring while pyridines only have a 6 member ring.
What is the equation for recombinant frequency (RF)?
Number of recombinant offspring/ Total number of offspring X 100 to get %
How do you determine genetic Distance?
the reombination frequency % = the # of map units or centiMorgans.
What is the maximal map unit distance between genes?
50 map units
What are the four steps in 3 point mapping?
1 - Arrangement of alleles (of trihybrid parent)
2 - Order of alleles-which gene is in the middle?
3 - Map distance between the genes
4 - interference
What is complete interference?
No double-crossovers occur
What is positive interference?
if fewer double-crossover evens than expected occur
What is negative interference?
If more double-crossover event than expected occur
What is no interference?
When DCO = DCE
What is interference (I)?
It reduces expected number of multiple crossovers when crossover event in one region of chromosome inhibits second event nearby.
What us the Coefficient of coincidence (C) and what is the equation?
-Quantifies disparities resulting from interference
C = Observed DCO - Expected DCO
