Term
| What mutation causes Hutchinson-Gilford Progeria? |
|
Definition
| A mutation in the gene for Lamin A, a nuclear membrane scaffolding protein. Found on chromosome 1. |
|
|
Term
| What techniques are used to study heritable diseases? |
|
Definition
| Twin studies, adoption studies, pedigrees. |
|
|
Term
| Who was the holocaust doctor that used unethnical human experiments to learn about genetics? |
|
Definition
|
|
Term
| Why is the study of human genetics difficult? |
|
Definition
| Long generation time, controlled matings not possible, family size (n) is small. |
|
|
Term
|
Definition
| Mating between related persons. |
|
|
Term
| Give an example of an autosomal dominant syndrome. |
|
Definition
| Waardenburg Syndrome, a type of deafness associated with a white forelock and vision problems. |
|
|
Term
| What are some characteristics of autosomal recessive traits? |
|
Definition
- Equal distribution
- Tend to skip generations
- Tend to appear in children of related parents
|
|
|
Term
| What are some characteristics of autosomal dominant traits? |
|
Definition
- Equal distribution
- Unaffected do not transmit trait
- Affected have at least one affected parent
|
|
|
Term
| What are some characteristics of X-linked recessive traits? |
|
Definition
- Appear frequently in males
- Affected male does not pass trait to son
- Can pass allele to daughter
|
|
|
Term
|
Definition
| An x-linked recessive trait, where there is an absence of protein required for clotting. |
|
|
Term
| Who created the first genetic map? |
|
Definition
| Alfred Sturtevant mapped the X chromosome of Drosophila. |
|
|
Term
|
Definition
| The sorting of alleles into new combinations, happens by independent assortment of alleles. |
|
|
Term
| Who discovered the non-independent assortment of alleles? |
|
Definition
| Bateson, Saunders, and Punnett in 1905. |
|
|
Term
| What are the characteristics of linked genes? |
|
Definition
- Genes that are located close together on a chromosome
- They belong to the same linkage group
- Travel together during meiosis (same gamete)
- Do NOT assort independently
- Are inherited together
|
|
|
Term
| What is an example of recombination? |
|
Definition
| Crossing over during meiosis |
|
|
Term
| How did Meselson and Stahl demonstrate that replication in E. coli occurs in a semiconservative manner? |
|
Definition
| They incorporated different isotypes of nitrogen into DNA and then weighed it to see how it mixed. Equilibrium density gradient centrifugation. |
|
|
Term
| What is the origen of replication in E.coli? |
|
Definition
|
|
Term
| What is heteroduplex DNA? |
|
Definition
| DNA formed during a Holliday Junction, where the DNA molecule has 2 strands, one from each chromosome. |
|
|
Term
| What is one way that crossing over occurs? |
|
Definition
|
|
Term
| What did Creighton and McClintock use to discover intrachromosomal recombination? |
|
Definition
| The abnormal corn chromosome 9, which has a knob and an extra piece. |
|
|
Term
|
Definition
Should take place during the 17th to 18th week of pregnancy, cells from the amniotic fluid are sampled to run genetic tests. |
|
|
Term
| What is chroionic villus sampling? |
|
Definition
| In the 10th to 12th week of pregnancy sampling of the blood from the villus containing fetal cells. |
|
|
Term
| What are characteristics of linked genes? |
|
Definition
located close together on the chromosome belong to same linkage group travel to same gamete during meiosis do NOT assort independently inherited together
|
|
|
Term
| What are the two ways that linked alleles can be arranged on homologous chromosome? |
|
Definition
| Coupled (cis) or repulsion (trans) |
|
|
Term
What is the resulting cell called in somatic cell hybridization? |
|
Definition
|
|
Term
| What are some physical ways of gene mapping? |
|
Definition
| Deletion mapping, somatic cell hybridization, fluorescent molecular probes. |
|
|
Term
| Describe transcription initiation in a prokaryote. |
|
Definition
Circular E. coli has 1 oriC Iniator protein binds to oriC causing a short section of DNA to unwind Allows helicase to attach to polynucleotide strand
|
|
|
Term
| Describe unwinding in prokaryotic transcription. Is it different than in eukaryotic? |
|
Definition
DNA helicase breaks H-bond between 2 strands
Moves along 5´--> 3 ´ direction (replication fork) |
|
|
Term
| How does DNA polymerase III work in prokaryotes? |
|
Definition
Polymerase activity = adds nucleotides to the 3´
Exonuclease activity = removes nucleotides 3´5´ (corrects errors) |
|
|
Term
| How does DNA polymerase I work (prokaryotes)? |
|
Definition
Polymerase and exonuclease activity similar to polyIII
Exonuclease activity 5´3´
Removes primers and replaces with DNA nucleotides 5´3´ |
|
|
Term
| What are the steps of transcription in eukaryotes? |
|
Definition
Licensing of DNA Replication
Replication licensing factor attaches to origin
Unwinding
Polymerization (polymerases)
Elongation
Nucleosome assembly (histones)
Termination |
|
|
Term
| What does does RNA polym. I transcribe? |
|
Definition
|
|
Term
| What does RNA polym. II transcribe? |
|
Definition
| pre-mRNA, snRNA, snoRNA, some miRNA |
|
|
Term
| What does RNA polym. III transcribe? |
|
Definition
| tRNAs, small rRNAs, snRNAs, miRNAs |
|
|
Term
| What does RNA polym. IV transcribe? |
|
Definition
|
|
Term
| What is a consensus sequence? |
|
Definition
| A consensus sequene consists of the most commonly encountered bases at each position in a group of related sequences |
|
|
Term
| In bacterial promoters, where are consensus sequences found? |
|
Definition
| Upstream of the start site, typically at -35 and -10 |
|
|
Term
| How does eukaryotics promoter recognition occur? |
|
Definition
| By accessory proteins (transcription factors) that bind to the promoter and recruit specific RNA polymerases. |
|
|
Term
| What is the core promoter region? |
|
Definition
located upstream of the gene site where basal transcription apparatus binds includes consensus TATA box
|
|
|
Term
Where are regulatory promoters found? |
|
Definition
| Upstream of the core promoter (TATA typically) |
|
|
Term
| What is the concept of colinearity? |
|
Definition
| That each gene encodes for one protein. |
|
|
Term
| Who discovered the validity of the one gene one enzyme theory? |
|
Definition
| 1958 Beadle and Tatum used neurospora to prove this theory. |
|
|
Term
|
Definition
|
|
Term
| What is a somatic mutation? |
|
Definition
| A mutation in cells not producing gametes, passed on to daughter cells in mitosis, normal cells compensate. |
|
|
Term
| What are germ-line mutations? |
|
Definition
| Passed to future generations because they occur in cells producing gametes, offspring will carry mutations in all somatic and germ-line cells. |
|
|
Term
|
Definition
| A small DNA lesion that affects a single single. |
|
|
Term
| What is chromosomal mutation? |
|
Definition
| A large-scale genetic mutation affecting chromosome structure and function and therefore multiple genes. |
|
|
Term
| What is base substitution? |
|
Definition
| A type of gene mutation where a single nucleotide is altered. |
|
|
Term
|
Definition
| When a purine is replaced by a purine in base substitution, or a pyrimidine with a pyrimidine. |
|
|
Term
| What are the purines, and what are the pyrimidines? |
|
Definition
| Purines are A and G, Pyrimidine are C and T. |
|
|
Term
| What are insertions and deletions? |
|
Definition
| Types of gene mutations where one or more nucleotide pairs are inserted or deleted, leading to a shift in the reading frame. |
|
|
Term
| What are expanding trinucleotide repeats? |
|
Definition
| Gene mutations in which the number of copies of a set of three nucleotides (trinucleotide) is increased in number. # of repeats correlates with the severity of the disease. |
|
|
Term
| What is an example of a disease where trinucleotide repeats occurs? |
|
Definition
| In 1991 they observed that the FMR-1 gene causes fragile X, severe form of mental retardation. The tip of the X chromosome is attached by only a slender thread. |
|
|
Term
|
Definition
| The severity of the disease gets more severe with each generation. |
|
|
Term
| What is a forward mutation? |
|
Definition
| Alters the wild type phenotype to a mutant phenotype. |
|
|
Term
| What is a reverse mutation? |
|
Definition
| Alters a mutant phenotype back to a wild type phenotype. |
|
|
Term
| What is a suppressor mutation? |
|
Definition
| A genetic mutation that hides or suppresses the effect of another mutation (double mutant). Occurs at a site that is distinct from the site of the original mutation, thus they are a double mutant. |
|
|
Term
| Base substitutions can cause what three effects? |
|
Definition
| Missense, nonsense, and silent mutations. |
|
|
Term
| What does a missense mutation do? |
|
Definition
| The new codon encodes for a different amino acid, leading to a change in AA sequence. |
|
|
Term
| What does a nonsense mutation do? |
|
Definition
| The new codon is a stop codon, there is premature termination of translation. |
|
|
Term
| What does a silent mutation do? |
|
Definition
| The new codon encodes for the same amino acid as the original codon, there is no change in AA sequence. |
|
|
Term
| What is a loss of function mutation? |
|
Definition
| Complete or partial absense of normal protein function, alters structure of the protein, no longer functional, can occur at the level of transcription, translation, or splicing of the protein. |
|
|
Term
| What is a gain of function mutation? |
|
Definition
| Produces an entirely new trait, appearing in inappropriate tissue or in the wrong time of development, can affect receptors for growth factors and stimulate growth in the absense of GF - i.e. cancer |
|
|
Term
| What factors affect mutation rates? |
|
Definition
- How often in the DNA
- Will it be repaired (effective or faulty repair)
- Will it be recognized and recorded
|
|
|
Term
|
Definition
| A dominant dwarfism mutation occuring in 4 out of every 10,000 people. |
|
|
Term
| What is a spontaneous mutation? |
|
Definition
| A natural change in the DNA structure, includes tautomeric (H changing position), and mispairing due to wobble base pairing, as well as insertions and deletions |
|
|
Term
| How do insertions and deletions occur? |
|
Definition
| Strand slippage, where strand forms small loops, or unequal crossing over (duplicated copies of sequence) |
|
|
Term
| How does strand slippage occur? |
|
Definition
| If the new strand slips and forms a bubble, an insertion will occur to compensate, if it occurs on the template strand a deletion will occur. |
|
|
Term
| What is an example of early research on chemically induced mutations? |
|
Definition
| Charlotte Aeurbach's research in the mid 1900's on Mustard gas and fruit flies, which reduces the viability of gametes. It was used during WWI. |
|
|
Term
| What are four types of chemically induced mutation? |
|
Definition
| Alkylation (O beomes alkyl group), deamination (amine group becomes O), hydroxylation (group becomes hydroxyl group), oxidative (reactive oxygen damages DNA causing mispairing by adding O to nucleotide) |
|
|
Term
| What type of chemical mutagenesis is used in chemotherapy for cancer? |
|
Definition
| Alkylation is used to damage the DNA of cancer cells, using a line of drugs known as alkylating antineoplastic agents. |
|
|
Term
|
Definition
| X-rays and cosmic rays provide high energy, penetrate the tissues and damage DNA by dislodging e- (free radicals), and repair fail = death. Can form thymine dimers this way. |
|
|
Term
| What test is used to identify whether a compound can cause cancer? |
|
Definition
| The Ames test, shows whether number of colonies on a plate is increased due to the presense of chemical in question. |
|
|
Term
| What are the four types of DNA repair mechanisms? |
|
Definition
| Mismatch, direct, base excision, and nucleotide extension. |
|
|
Term
| What is the mismatch repair system? |
|
Definition
| Repairs replication errors, including mispaired bases and strand slippage. |
|
|
Term
| What is the direct repair system? |
|
Definition
| Repairs pyrimidine dimer, other specific types of alterations. |
|
|
Term
| What is the base excision repair system? |
|
Definition
| Repairs abnormal bases, modified bases, and pyrimidine dimers. |
|
|
Term
| What is the nucleotide excision repair system? |
|
Definition
| Repairs DNA damage that distorts the double helix, including abnormal bases, modified bases, and pyrimidine dimers. |
|
|
Term
| What is an example of a disease that results from defects in DNA repair? |
|
Definition
| Xeroderma pigmentosum, freckle-like spots on the skin and predisposition to cancer. |
|
|
Term
|
Definition
| A series of mutations, genetics, but not often hereditary. |
|
|
Term
| What are the characteristics of abnormal cell growth leading to cancer? |
|
Definition
| Inability to respond to normal cell signals, uncontrolled proliferation, and loss of cell integrity where normal cells are crowded out. |
|
|
Term
| What are three types of cancer cells? |
|
Definition
| Benign (localized tumor), malignant (invades nearby tissues), and matastic (travel and establish secondary tumors). |
|
|
Term
| What is pancreatic cancer? |
|
Definition
| Cancer of the pancreas is inherited as an autosomal dominant trait in a family that possesses a mutant palladin gene, an identical mutation on exon 2. |
|
|
Term
| What is the palladin gene? |
|
Definition
| Important in pancreatic cancer, palladin encodes for an essential component of the cell's cytoskeleton, when mutated it contributes to the spread of the cancer. |
|
|
Term
| What are some early observations that indicated cancer was a genetic disease and was inherited? |
|
Definition
| They result from genetic chance, they are associated w/ chromosomal abnormalities, and they seem to run in families i.e. are inherited. |
|
|
Term
| What later observations disproved that cancer is usually inheritable? |
|
Definition
| If inherited, every cell should receive the gene, tumors only appear in specific tissue, and many cancers don't run in families. |
|
|
Term
| Who proposed the multistep model of cancer? |
|
Definition
| Alfred Knudson in 1971, using retinoblastoma - two different mutations were necessary for cancer to occur. |
|
|
Term
| What is clonal evolution of tumors? |
|
Definition
| Tumor cells acquire multiple mutations as they divide, allowing them to become increasingly aggressive and proliferate, eventually the cell becomes malignant and divides uncontrollably, invading other tissues. |
|
|
Term
| What contributes to the frequency of clonal evolution? |
|
Definition
| How often mutations arise, the integrity of DNA repair mechanisms, and what genes are mutated, i.e. ones affecting chromosomal segregation (aneuploid) |
|
|
Term
| What are the types of signals that regulate cell division? |
|
Definition
| Molecules that stimulate division, and those that inhibit. |
|
|
Term
| What type of cell signaling occurs in normal cells? |
|
Definition
| Stimulatory and inhibitory molecules are present at the same time, causing proper speed. |
|
|
Term
| What are the two types of signaling genes in cell division? |
|
Definition
| Oncogenes stimulate cancer, tumor-suppresor genes inhibit cancer. |
|
|
Term
| Stimulatory genes are usually ... |
|
Definition
|
|
Term
| Inhibitory genes are usually ... |
|
Definition
|
|
Term
| Who and how was the first discovery of oncogenes proposed? |
|
Definition
| In 1909 physician Peyton Rouse injected tumor into one hen from another, tumor was transmitted by a virus (Rous sarcoma), assumed that the virus carried a cancer causing gene, SRC (1970). |
|
|
Term
| What did Michael Bishop & Harold Varmus do in 1975? |
|
Definition
| Used probes for viral oncogenes in normal cells, genome of normal DNA had same sequence as viral oncogene = proto-oncogenes. |
|
|
Term
| When a virus infects a cell, what occurs? |
|
Definition
| A proto-oncogene may incorporate (recombination), within the viral genome, proto-oncogene can mutate into an oncogene, and can then insert back into the cell, causing rapid proliferation. |
|
|
Term
| What type of viruses typically cause cancer? |
|
Definition
|
|
Term
| How do retroviruses cause cancer? |
|
Definition
| They can mutate and rearrange proto-oncogenes into oncogenes, and they can also insert strong promoters near proto-oncogenes. |
|
|
Term
| What are some mutations of oncogenes as the result of viruses? |
|
Definition
| The sequence of the proto-oncogene can be altered or truncated, it can be incorporated next to a viral promoter or enhancer leading to over expression, or the function of the gene may be altered when the proto-oncogene is inserted into viral DNA. |
|
|
Term
| Tumor suppressor genes are more or less difficult to identify than oncogenes? Why? |
|
Definition
| More difficult because 2 alleles must mutate (they are recessive), because they FAIL to function harder to indentify, insert back to cell causes rapid proliferation. |
|
|
Term
| How does a tumor supressor gene cause cancer? |
|
Definition
| When the inactivation or loss of a functional allele occurs (loss of heterozygosity) this leads to cancer. |
|
|
Term
| What is haploinsufficiency with respect to tumor suppressor genes? |
|
Definition
| The appearance of a trait in an individual cell or organism that is heterozygous for a recessive trait, dosage effects occur because normal product is produced to suppress, but not enough is present. |
|
|
Term
| What is significant about heterozygosity for a tumor suppressor gene? |
|
Definition
| These people are predisposed to cancer because only one mutation, such as chromosomal deletion, can cause cancer by loss of the wild type allele and thus loss of suppressor activity. |
|
|
Term
| What is p53, and where is it found? |
|
Definition
| p53 is a tumor suppressor gene found in the nucleus, it acts as a transcription factor, and regulates apoptosis. |
|
|
Term
| Cell cycle progression is governed primarily by what? |
|
Definition
| Cyclins, CDK's, which function by phosphorylating proteins and thus activating or de-activating them. |
|
|
Term
|
Definition
| They specificy which proteins CDK will phosphorylate, each cyclin appears at specific points in the cell cycle, its synthesis and destruction are regulated by other cyclins. |
|
|
Term
| What is the RB protein and how does it function? |
|
Definition
| The retinoblastoma protein helps control the progression through the G1/S checkpoint by binding transcription factor E2F. |
|
|
Term
| What is the G1/S checkpoint? |
|
Definition
| In G1, just before the cell enters S phase and replicates its own DNA. |
|
|
Term
| How does the RB/E2F complex function? |
|
Definition
| RB binds to E2F and keeps it inactive, increasing concentrations of cyclin-D-CDK and E-CDK phosphorylate RB which activates RB and RB releases E2F. E2F then binds to DNA and stimulates the transcription of genes required for replication - i.e. the cell moves into S phase. |
|
|
Term
| What is the G2/M checkpoint controlled by and how does it work? |
|
Definition
| Progression through the G2/M checkpoint is regulated by cyclin B. MPF, mitosis-promoting factor, is formed from cyclin B combining with CDK. During G1 cyclin B levels are low, so amount of MPF is low. As more cyclin B is produced to combine with CDK, MPF increases. Near the end of G2 the amount of MPF reaches a critical level and commits the cell to divide. MPF rises until it reaches its peak in mitosis. |
|
|
Term
|
Definition
| Mitosis promoting factor, when activated, phosphorylates other proteins - MPF is a KINASE. It induces nuclear-membrane breakdown, spindle formation, and chromosome condensation that occur during prophase. |
|
|
Term
| What happens when high or low levels of MPF are present? |
|
Definition
| When high levels are present mitosis is stimulated, when low, return to interphase conditions. |
|
|
Term
| What occurs when a mutation in the RB gene arises? |
|
Definition
| The cell is not held in G1, proceeds to division. |
|
|
Term
| What happens when the over-expression of genes encoding cyclin D occurs? |
|
Definition
| Stimulates the passage through the G1/S checkpoint |
|
|
Term
| What does a mutation of the p53 gene cause? |
|
Definition
| No regulation of CDK and no intitiation of apoptosis. |
|
|
Term
| What does a mutation in the signal transduction pathway cause? |
|
Definition
| External signals that trigger a cascade of intracellular reactions to produce a response. |
|
|
Term
| How does angiogenesis occur? |
|
Definition
| Stimulated by growth factors, highly regulated. In cancer the angiogenesis genes are over expressed, metastasis occurs. Genes contribute to metastasis, they encode components of the extracellular matrix and cytoskeleton, as well as adhesion proteins that hold cells together. |
|
|
Term
| What types of chromosomal arrangement may occur in cancer? |
|
Definition
| Deletion, inversion, translocation. |
|
|
Term
| What is deletion with respect to chromosomes in cancer? |
|
Definition
| The loss of tumor supressor genes. |
|
|
Term
| What is inversion with respect to chromosome rearrangement and cancer? |
|
Definition
| Segments of the chromosome are inverted end to end, may happen in a tumor supressor gene, causing inactivation. |
|
|
Term
| What happens in translocation, with respect to chromosome rearrangement in cancer? |
|
Definition
| Sequences from 2 different chromosomes are brought together, and generate a fused protein that stimulates cancer processes. |
|
|
Term
| What is an example of chromosomal translocation? |
|
Definition
| Chronic myelogenous leukemia, caused by translocation in chromosomes 9 and 22. Affects bone marrow cells, stimulates unregulated cell division. |
|
|
Term
| What is another example of chromosomal translocation? |
|
Definition
| Burkitt lymphoma (b cell), translocation between chromosomes 8 and 14 cause the lymphoma, which is cancer of the b cells. C-MYC is the cancer causing gene, comes under control of regulatory sequences that activate Ig. |
|
|
Term
| What is an example of spindle mutations? |
|
Definition
| Advanced colon cancer, the cells possess chromosomal abnormalities, including extras, missing, and rearrangements. |
|
|
Term
| What are the technical names of a benign tumor and a malignant tumor? |
|
Definition
|
|
Term
| What are restriction enzymes? |
|
Definition
| Restriction endonucleases cut DNA at specific point known as restriction sites, they were discovered in the 1960's as bacteria's natural defense against viruses. |
|
|
Term
| How does bacteria protect itself from it's own restriction enzymes? |
|
Definition
|
|
Term
| What are the 3 classes of RE, and which is most commonly used? |
|
Definition
| Types I and III cut at sites outside of the recognition sequence (4-6 bp palindrome), type II are more commonly used, cut at sites within the recognition sequence. |
|
|
Term
| What enzyme connects sticky ends? |
|
Definition
|
|
Term
| How can the fragments of gel electrophoresis be viewed? |
|
Definition
| Stained with dye (ethidium bromide), or a radioactive label (32P). |
|
|
Term
| What does an idealized cloning vector have? |
|
Definition
| An origen, selectable markers, unique resstriction sites. |
|
|
Term
| Describe a typical plasmid vector. |
|
Definition
| Circular DNA naturally occurring in bacteria, insert gene of interest and then introduce into bacteria via transformation, stable w/ DNA <15kb, pUC19 contains the lacZ and ampicillin resistance markers. |
|
|
Term
| How can a foreign piece of DNA be inserted into a vector? |
|
Definition
| Using restriction enzymes and ligase. |
|
|
Term
| What is an expression vector? |
|
Definition
| Instead of inserting the foreign gene into the selectable marker, the gene may be inserted into an expression vector, which contain operon sequence that allow inserted DNA to be transcribed and translated. |
|
|
Term
| What are the required reagents for PCR? |
|
Definition
| Template DNA, DNA polymerase, dNTPS, primers, magnesium ions, salts, thermocycler |
|
|
Term
| What are the limitations of PCR? |
|
Definition
| Must know the DNA sequence, contamination occurs easily, Taq doesn't proofread, only small pieces of DNA can be amplified. |
|
|
Term
| What are microsatelites and STR'S? |
|
Definition
| Very short DNA sequences repated in tandem and found widely within the genome. Can identify relationships, etc. |
|
|
Term
| How can siRNA's be produced? |
|
Definition
| By cloning DNA sequences corresponding to the siRNAs between two strong promoters. When cloned into an expression vector, both DNA strands will be transcribed and the complementary RNA molecules will anneal to form double stranded RNA that will be processed into siRNA by dicer. |
|
|
Term
| The theory of preformationism states that humans come from a preformed structure containing a mini human? |
|
Definition
|
|
Term
| What purpose does the nucleosome serve and what is it? |
|
Definition
| Complex of DNA and histone proteins that forms chromatin, enables DNA to fit within the nucleus, limits access to DNA by proteins. |
|
|
Term
| What are the typical DNA compartmentalization schemes by prokaryotes and eukaryotes respectively? |
|
Definition
| Prokaryotes do not have have histones, have a circular molecule of DNA, Eukaryotes do have histones, and have multiple, linear DNA. |
|
|
Term
| What are the parts of a duplicated chromosome? |
|
Definition
| Sister chromatids, joined at the centromere by the kinetochore where the spindle microtubules attach. |
|
|
Term
| Which phases of meiosis contribute to genetic variation? |
|
Definition
| Prophase I and anaphase I and II. |
|
|
Term
| What is the law of equal segregation? |
|
Definition
| During meiosis alleles of a single gene segregate equally into gametes, 50% of the gametes carry one allele, 50% carry the other. |
|
|
Term
| What is the principle of independent assortment? |
|
Definition
| That alleles at different loci separate independently of one another. |
|
|
Term
| What is the binomial expansion? |
|
Definition
Predicts probability of an event occurring
(p + q)^n
p = probability of child affected
q = probability of child normal
n = number of subjects (children)
|
|
|
Term
|
Definition
| A lack of the Y chromosome, short, low hairline, broadchest, folds of skin neck, normal intelligence. |
|
|
Term
| What is Klinefelter Syndrome? |
|
Definition
| XXY, causes small testes, sterile, less facial and pubic hair, normal intelligence. |
|
|
Term
| What is the male determining gene? |
|
Definition
| SRY, located on the short arm of the Y chromosome. |
|
|
Term
|
Definition
| An x-linked recessive trait. |
|
|
Term
|
Definition
| An inactive x chromosome, shut off for dosage compensation, equalizes the amount of protein produced by x-linked genes in the two sexes. |
|
|
Term
| What is an example of codominance in humans? |
|
Definition
|
|
Term
|
Definition
| The degree to which a character is expressed. |
|
|
