GiM AfLs

Question 1

Shape of the mitochondrial genome?

Answer 1

Circular

The mitochondrial genome is a remnant of the ancestral chromosome of the symbiotic bacterium-like organism from which mitochondria are believed to have evolved. It replicates independently of the nuclear genome, and is also transmitted independently (cytoplasmic inheritance). When it comes to germline transmission, all of an embryo’s mitochondria derive from the oocyte (not the sperm), so that fathers cannot transmit mutations that lie within the small mitochondrial DNA circle. This is “non-nuclear” inheritance.

Question 2

Okazaki fragments take part in which process to do with DNA?

Answer 2

Replication

Because the two strands of the DNA double helix run in opposite directions, only one of them can be copied continuously as the helix unwinds at the replication fork. The other must the made in chunks, each one initiated by an RNA primer. These Okazaki fragments must later be stitched (“ligated”) together.

Question 3

A term used to describe how a genetic change manifests itself.

Answer 3

Phenotype

The O.E.D. definition of phenotype: “The sum total of the observable characteristics of an individual, regarded as the consequence of the interaction of the individual’s genotype with the environment; a variety of an organism distinguished by observable characteristics rather than underlying genetic features.”

Question 4

This element is the most widespread class of retrotransposon in the human genome.

Answer 4

Alu

A large proportion of the genome comprises interspersed repeat elements that have dispersed around the genome by retrotransposition. Most of these “jumping” DNA elements are no longer active, but a small proportion are, so that new integration events occur every so often.

Question 5

Vertical (parent to child) inheritance of a disorder is typically seen for autosomal ——– conditions.

Answer 5

Dominant

Autosomal dominant disorders are caused by heterozygous mutations, transmitted to offspring with a 50% probability.

Question 6

This region of the chromosome separates the short and long arms.

Answer 6

Centromere

The centromere is seen down the microscope as a narrow region of the chromosome, where the sister chromatids are held together. This region is also crucial for attachment of the chromosome to the mitotic spindle (at the kinetochore).

Blocks of repetitive DNA sequence are found at the centromere and are required for its assembly, notably alphoid repeat sequences, which are unique to each chromosome and can be used as specific detection reagents.

Question 7

Familial adenomatous _________ is an inherited condition that predisposes to bowel cancer.

Answer 7

Polyposis

Familial adenomatous polyposis (FAP) is also known as adenomatous polyposis coli (APC). It is an autosomal dominant condition in which thousands of benign polyps (adenomas) develop in the colon in early adult life. One or more of these eventually becomes a malignant colon cancer.

Question 8

Parental consanguinity increases the risk of genetic diseases showing this inheritance pattern.

Answer 8

Recessive

Parental consanguinity increases the risk that a couple will both be carriers of the same recessive mutation. Rare recessive diseases therefore occur with increased frequency in such families.

Question 9

This type of enzyme synthesizes DNA and RNA.

Answer 9

Polymerase

Polymerases are diverse in their biochemical properties, including whether they make DNA or RNA. They are, of course, vital biological molecules, but have also been co-opted by scientists for use as laboratory tools.

Question 10

This term is used to refer to increasing severity of an inherited disease as it passes down successive generations.

Answer 10

Anticipation

Anticipation can be an “ascertainment artefact” (milder disease only noticed in a parent after referral of a more severely affected child) but has a real biological basis for some disorders.

Question 11

A unit of chromatin, comprising about 200 bp of DNA wound around a histone core.

Answer 11

Nucleosome

Nucleosomes are the first level of assembly of the genome into chromatin. The histones are not just passive building blocks – they play an important role in gene regulation, through a large range of chemical modifications.

Question 12

Ours consists of 46 chromosomes and was first correctly defined in 1956.

Answer 12

Karyotype

a. The chromosomal constitution of a cell (and hence of an individual, species, etc.) as determined by the number, size, shape, etc., of the chromosomes (usually, as observed at metaphase during cell division).
b. A systematized representation of the chromosomes of a cell or cells, esp. a photographic one.

Both these definitions of karyotype are from the O.E.D. and both are commonly used in genetics. The human karyotype was believed to have 48 chromosomes until correctly visualized for the first time.

Question 13

An individual who is heterozygous for a recessive mutation.

Answer 13

Carrier

This is a somewhat imprecise term, but one that is quite widely used. The “carrier frequency” for some of the less rare recessive diseases may be quite high, raising the question of whether screening of individuals from the general population is justified or desirable.

Question 14

That part of a gene which is excised from the RNA transcript by splicing.

Answer 14

Intron

Exons, which include the protein-coding part of the genome, are defined as the parts of the gene that end up in the mature spliced RNA product. They comprise about 2% of our DNA. Because most disease-causing mutations occur in exons, a popular “short-cut” version of genome analysis consists of sequencing all the exons—a so-called exome analysis. Introns separate the exons and must be precisely excised to allow “reconstruction” of the protein-coding mRNA.

Question 15

The Philadelphia chromosome is characteristic of chronic ___________ leukaemia.

Answer 15

Myelogenous

The Philadelphia chromosome is a translocation between chromosomes 9 and 22: t(9;22)(q34;q11). It is found in the leukaemic cells of chronic myelogenous leukaemia (CML) and results in the production of an abnormal fusion protein BCR-ABL, due to the joining of the ABL and BCR genes on those two chromosomes. The BCR-ABL protein can be targeted with specific tyrosine kinase inhibitors that are effective in the treatment of CML.

Question 16

An evolutionary remnant, in the form of a DNA sequence that resembles a gene elsewhere in the genome, but has mutations that appear to render it inactive.

Answer 16

Pseudogene

Pseudogenes have arisen during evolution by gene duplication, but have subsequently mutated and lost their functions. They are a normal widespread feature of the human genome. Because some of them are extremely similar in sequence to their functional siblings, they can interfere with laboratory analysis aimed at examining the functional gene.

Question 17

A genetic change.

Answer 17

Mutation

Any genetic change is, by definition, a mutation. However, sometimes, the word is used in a way that implies that the change in question also has a phenotypic effect (particularly a harmful one).

Question 18

An individual version or genetic variant at a particular locus.

Answer 18

Allele

The O.E.D. definition is nice and clear: “Each of two or more alternative forms of a gene that arise by mutation and which may be found in the same position on a homologous chromosome.” This is a “new word” invented by geneticists, but if you understand what is meant by it, and use it correctly, you will be much better placed to grasp any discussion dealing with genetic variation—which itself is central to why genetics affects human health.

Question 19

What term describes a 45,XX,-21 chromosome makeup?

Answer 19

Monosomy

Autosomal monosomies are not compatible with life, but may be detected in spontaneous abortions. Monosomies may also develop as acquired abnormalities in tumour cells.

Question 20

Advanced ** age is a major risk factor for numerical chromosome abnormalities

Answer 20

Maternal

Question 21

The MYCN oncogene is characteristically amplified in this childhood tumour

Answer 21

Neuroblastoma

An example of somatic chromosome abnormality in cancer. Another common example is amplification of the growth factor receptor ERBB2 in breast cancer. These acquired genetic changes are important indicators of prognosis.

Question 22

Cytogenetic technique that uses a DNA probe to examine a single locus

Answer 22

Fluorescent in situ hybridization (FISH)

Question 23

Chromosomal inversion with both breakpoints on the same arm

Answer 23

Paracentric

pericentric = around the centromere (cf. pericardial = around the heart)

paracentric = beside the centromere (cf. parathyroid = beside the thyroid)

Question 24

A type of translocation in which two acrocentric chromosomes are fused

Answer 24

Robertsonian

The vestigial short arms of acrocentric chromosomes differ in content from other chromosome arms. They contain no indispensible single-copy genes. What then is on the short arms of acrocentric chromosomes? (Look it up.)

Question 25

Stage of cell cycle during which DNA replication occurs

Answer 25

Interphase Interphase occupies most of the cell cycle duration. It is divided into G1, S and G2 phases, separated by regulatory checkpoints. DNA replication occurs during S (synthesis) phase, after which the cell has twice the normal DNA content. Consequently, when the chromosomes have later condensed and aligned on the spindle at metaphase, each chromosome is made up of two sister chromatids.

Question 26

Turner syndrome (45,X) and Klinefelter syndrome (47,XXY) are examples of sex chromosome **********

Answer 26

Aneuploidy

Question 27

Situation in which there are two or more cell populations in an individual, differing in genetic makeup

Answer 27

Mosaicism Mosaicism results from genetic changes that occur after the embryo has started to develop. In other words, these changes are due to mitotic errors, rather than meiosis. An individual may be mosaic for a chromosome abnormality (e.g. mosaic trisomy 21) or for any other genetic change (like a point mutation). The consequences of mosaicism are difficult to predict, since they depend not only on the nature of the genetic change, but also on the spatial distribution of the mutant cells within the whole organism.

Question 28

_____ CGH is the front-line method for testing for chromosomal imbalance

Answer 28

Array You should understand that aCGH and similar methods cannot detect balanced rearrangements (e.g. balanced reciprocal translocations). Only dosage changes will be detected.

Question 29

Set of chromosomes in an individual

Answer 29

Karyotype

Question 30

Sanger sequencing depends on the synthesis of DNA strands in the presence of chain _______

Answer 30

Terminators Chain-terminating nucleotide analogues (typically 2′,3′-dideoxynucleoside triphosphates, ddNTPs) produce sets of nested fragments, all ending with the same base (A,C,G or T). The sizes of these fragments then provide a read-out of the positions of that base in the sequence.

Question 31

A _______ gene syndrome refers to a disorder in which genes that are adjacent are simultaneously affected by a chromosomal rearrangement

Answer 31

Contiguous A good example is WAGR syndrome, caused by deletion of the adjacent WT1 and PAX6 genes.

Question 32

Potentially life-threatening type of congenital malformation common in children with Down syndrome

Answer 32

Cardiac About half of Down syndrome babies have a structural abnormality of the heart which may need urgent surgical repair. Gastrointestinal problems are also common, including duodenal atresia.

Question 33

DiGeorge Syndrome is a common deletion syndrome on which chromosome?

Answer 33

Chromosome 22

Question 34

Chemical group added to cytosine bases in genomic DNA after replication

Answer 34

Methyl Very important for gene regulation

Question 35

The set of all the exons in the genome

Answer 35

Exome The exome is not a naturally occurring entity; it is a conceptual collection of all the discontinuous exon segments in the genome. There are ways to isolate all these segments for DNA sequencing, which is a 50-fold smaller job than sequencing the entire genome.

Question 36

A genetic ********** results in reduced diversity

Answer 36

Bottleneck

Question 37

A type of translocation in which two different chromosomes exchange parts of chromosome arms.

Answer 37

Reciprocal Said to be balanced if no material is lost or gained.

Question 38

A splice _____ site is found at the 5' end of each intron in a gene.

Answer 38

Donor Splice donor and splice acceptor sites in the primary RNA transcript are recognized by the splicing machinery (“spliceosome”). They contain conserved sequence motifs, and mutations adjacent to the splice junctions are likely to impair splicing, and so are common causes of inherited disease.

Question 39

These chromosomes have vestigial short arms.

Answer 39

Acrocentric The short arms of acrocentric chromosomes differ in content from other chromosome arms. They contain no indispensable single-copy genes. What then is on the short arms of acrocentric chromosomes? (Look it up.)

Question 40

Stretches of this amino acid are encoded by the trinucleotide repeats involved in some neurodegenerative disorders.

Answer 40

Glutamine Glutamine (Gln, Q) is encoded by the codon CAG, and triplet repeats based on the sequence (CAG)n occur in a number of proteins. These repeats are generally polymorphic, but abnormally large repeat expansions result in the generation of proteins with larger than normal poly(Gln) stretches. The abnormal properties of these proteins result in neuronal damage, manifested through a variety of different late-onset neurodegenerative disorders. Anticipation is a feature of the inheritance of some of these.

Question 41

This type of mutation is not heritable.

Answer 41

Somatic Somatic mutations occur outside the germline. In general, that means that the cell in which a somatic mutation occurs will later give rise to daughter cells that differ from their surrounding colleagues. Provided such a mutation occurs early enough in development, the mutant cells may make up a substantial proportion of the individual. This is the situation known as mosaicism. Another consequence of somatic mutation (unusually later in life) is cancer, which is caused by a process of somatic mutation followed by selection of mutant cells and sequential further mutations.

Question 42

Point of meiotic recombination.

Answer 42

Chiasm Chiasmata are where crossing over between maternal and paternal chromosomes occurs during meiosis I. An essential part of gametogenesis, but also a source of errors resulting in chromosomal duplications and deletions.

Question 43

The proportion of the multifactorial causation of a common disease that can be attributed to genetic factors.

Answer 43

Heritability

Question 44

A tumour _____ gene is one that tends to prevent the emergence of the transformed phenotype in somatic cells

Answer 44

Suppressor Inactivating mutations of tumour suppressor genes underlie many inherited cancer syndromes. You need to understand the Knudsen “two-hit” mechanism for this.

Question 45

This type of codon can be TGA, TAA or TAG.

Answer 45

Stop or Terminator

Question 46

Women with BRCA1 mutations are at high risk of this type of cancer

Answer 46

Breast, ovarian, melanoma In men, prostate cancer is also higher risk.

Question 47

Describes the substitution of a chemically similar amino acid

Answer 47

Conservative

Question 48

This often hereditary childhood cancer involves the eye

Answer 48

Retinoblastoma

Question 49

Term to describe “identical” twins.

Answer 49

Monozygotic

Question 50

More than one gene contributes to the susceptibility to such a disease.

Answer 50

Polygenic Simple Mendelian inheritance patterns will not be observed for polygenic disorders.

Question 51

This syndrome results from a microdeletion including the elastin (ELN) gene.

Answer 51

Williams An example of a chromosomal imbalance syndrome due to a recurrent microdeletion of a small region of Chr. 7q11. Because of the presence of flanking genomic repeat elements, the same region is recurrently deleted or duplicated. There are distinctive medical consequences, including infantile hypercalcaemia, supravalvular aortic stenosis and peripheral pulmonary stenosis. The neurodevelopmental profile is also quite characteristic. Nicely illustrated in various ways by this video from the US Williams syndrome association.

Question 52

Type of genome-wide genetic study based in a population (rather than examining inheritance in families).

Answer 52

Association This is a common approach to identifying genetic contributions to common diseases or biologcial traits. Such studies (genome-wide association studies, GWAS) rely on the phenomenon of linkage disequilibrium (see elsewhere). This means that a statistically significant association of a particular marker allele with the disease under study has persisted for long enough that it is detectable among apparently unrelated members of entire population groups.

Question 53

______ disequilibrium means that alleles at two adjacent genetic loci are not randomly assorted into haplotypes.

Answer 53

Linkage If two polymorphic genetic marker loci (or marker locus and disease) are far apart on the chromosome (or on different chromosomes), they will be inherited independently of each other. If close together on the chromosome, in contrast, they will tend to be co-inherited, as chromosomal segments are handed on from parent to child. Despite this, over time, the two markers will be separated by occasional recombination between them, and so their alleles will reach equilibrium within a population. Only if markers are so close together that recombination between them is very rare indeed will disequilibrium persist between marker alleles. This means, for example that for loci A and B, allele A1 may be associated with allele B1 much more frequently than would be expected from the frequencies of the individual alleles A1, A2, B1, B2.

Question 54

A gene that has arisen by retrotransposition.

Answer 54

Processed gene Since this represents a reverse-transcribed copy of the mRNA, it lacks introns.

Question 55

The initiator codon specifies this amino-acid

Answer 55

Methionine (AUG)

Question 56

For a disorder with a substantial genetic component, one expects *********** to be greater in monozygotic than dizygotic twins.

Answer 56

Concordance

Question 57

A 69, XXY karyotype

Answer 57

Triploid The extra set of 23 chromosomes can be of maternal or paternal origin (digynic or diandric respectively, which affects the phenotype). Digynic triploids can very occasionally be live-born.

Question 58

This base is present in DNA but not RNA

Answer 58

Thymine T. In RNA, uracil is used. Thus ATG in DNA is transcribed into AUG in RNA. We tend to use DNA and RNA terminology interchangeably when referring to functional effects, for example describing codons: thus “terminator codons” = TGA/TAG/TAA (DNA) or UGA/UAG/UAA (RNA).

Question 59

A common genetic variant

Answer 59

Polymorphism Conventionally, a genetic variant should have an allele frequency of >1% to regarded as a polymorphism.

Question 60

In X-linked recessive inheritance, ******** carrier refers to a female who must be a carrier, based on her position in the pedigree.

Answer 60

Obligate Examples include a woman who has two affected sons, and one who is the daughter of an affected male.

Question 61

A single-nucleotide deletion would have this effect in a protein coding region

Answer 61

Frame shift Because they scramble and/or truncate the encoded protein beyond the mutation site, frameshift mutations are highly likely to damage protein function. Such a mutation close to the end of the open reading frame might still allow a functional protein to be made, but this tolerance is much less likely if the frameshift occurs earlier.

Question 62

************** instability is a hallmark of impaired DNA mismatch repair.

Answer 62

Microsatellite Mismatch repair is a process that allows replication errors to be recognized and put right. If this process is defective, errors in the DNA accumulate and eventually cause cancer. Deficient mismatch repair can be recognized through changes in size of short tandem repeat sequences (“microsatellites”). Microsatellite instability, “MSI”.

Question 63

A gene which does not tolerate loss of one copy

Answer 63

Haploinsufficient

Question 64

More than one gene contributes to the susceptibility to such a disease

Answer 64

Polygenic Simple Mendelian inheritance patterns will not be observed for polygenic disorders.

Question 65

This base is the one most commonly modified by DNA methylation

Answer 65

Cytosine Cytosine methylation occurs after DNA replication. It has important effects on gene regulation.

Question 66

Linkage ************** means that alleles at two adjacent genetic loci are not randomly assorted into haplotypes.

Answer 66

Disequilibrium If two polymorphic genetic marker loci (or marker locus and disease) are far apart on the chromosome (or on different chromosomes), they will be inherited independently of each other. If close together on the chromosome, in contrast, they will tend to be co-inherited, as chromosomal segments are handed on from parent to child. Despite this, over time, the two markers will be separated by occasional recombination between them, and so their alleles will reach equilibrium within a population. Only if markers are so close together that recombination between them is very rare indeed will disequilibrium persist between marker alleles. This means, for example that for loci A and B, allele A1 may be associated with allele B1 much more frequently than would be expected from the frequencies of the individual alleles A1, A2, B1, B2.

Question 67

A loss of a chromosome segment too small to be seen on metaphase chromosome banding.

Answer 67

Microdeletion Detectable by FISH (a targeted approach) or by array CGH (which looks at the whole genome). Williams syndrome (Chr. 7q) and DiGeorge syndrome (Chr. 22q) are examples of microdeletion syndromes

Question 68

A database of human chromosomal variation and its clinical effects, where a patient’s genomic imbalance can be compared to those of a large number of deposited cases.

Answer 68

DECIPHER

Question 69

Gene whose expression tends to cause or promote cancer development.

Answer 69

Oncogene

Question 70

In humans, this structure includes long stretches of the repeated sequence TTAGGG.

Answer 70

Telomere Mammalian telomeres are specialized structures that form the ends of the chromosomes. The telomere repeat sequences are synthesized by a dedicated enzyme complex known as telomerase.

Question 71

Inactivation of tumour suppressor genes often follows this model

Answer 71

Two hit

Question 72

Overgrowth syndrome due to dysregulation of the IGF2 gene

Answer 72

Beckwith (or Beckwith-Wiedemann syndrome) Insulin-like growth factor 2 (IGF2) is an important fetal growth regulator, and is encoded by an imprinted gene on Chr. 11p15.

Question 73

***** syndrome = hereditary nonpolyposis colon cancer (HNPCC)

Answer 73

Lynch This autosomal dominant disorder is due to defects in any of several genes involved in post-replicative DNA repair. This leads to a hallmark that can be used in its diagnosis – microsatellite instability (MSI)

Question 74

Type of genetic diagnostic test performed on in vitro cultured embryo.

Answer 74

Preimplantation

Question 75

A CpG ****** is cluster of CG dinucleotides frequently found near the 5' ends of genes.

Answer 75

Island CpG islands are regions of increased density of the normally depleted dinucleotide CG. They are usually unmethylated, but may undergo regulated methylation associated with changes in transcriptional activity.

Question 76

What does the “g” refer to in this mutation description: g. 8422106G>A?

Answer 76

Genomic

Question 77

Invasive method for obtaining fetal cells for prenatal genetic diagnosis.

Answer 77

Amniocentesis Chorionic villus sampling is the main prenatal diagnostic alternative

Question 78

********** P450 oxidases are encoded by a family of genes and are responsible for metabolizing many common drugs

Answer 78

Cytochrome Many members of this gene family are polymorphic, a notable example being the CYP2D6 gene, with clinically important consequences for variable response to many drugs, such as the breast cancer agent tamoxifen.

Question 79

Genes that are monoallelically expressed according to parent of origin are said to be *********

Answer 79

Imprinted Sometimes, though, it’s a little more subtle than just complete on/off: some imprinted genes are only monoallelically expressed at some stages of development; others may be monoallelic in one tissue and biallelic in another.

Question 80

Anticoagulant showing genetically-determined dosage sensitivity.

Answer 80

Warfarin

Question 81

The frequency with which an inherited disorder manifests itself in gene carriers

Answer 81

Penetrance This term is usually applied to dominant disorders, which frequently display incomplete penetrance. Penetrance values may be age-dependent, so for example, the penetrance of BRCA1 mutations might be ~30% at age 50 but 70% at age 70.

Question 82

A term for X-inactivation in females, named after its discoverer.

Answer 82

Lyonization

Question 83

Modifications to the tails of this class of proteins regulate gene expression

Answer 83

Histone

Question 84

The mitochondrial chromosome is…?

Answer 84

Circular

Question 85

A modification to the genome that does not affect the nucleotide sequence.

Answer 85

Epigenetic

Question 86

Genetic abnormality behind complete hydatidiform moles

Answer 86

Androgenesis Molar pregnancy is an abnormal form of pregnancy in which a non-viable fertilized egg implants in the uterus and will fail to come to term.

Question 87

********** methyltransferase shows genetic variation in activity that can cause toxicity on treatment with some cytotoxic drugs.

Answer 87

Thiopurine Side-effects due to bone marrow suppression can occur in individuals deficient in this enzyme. Drugs affected include azathioprine and 6-mercaptopurine.

Question 88

Genome browser - European style

Answer 88

ENSEMBL

Question 89

Uniparental ******: both copies of a chromosome from one parent.

Answer 89

disomy Uniparental disomy may be completely without clinical effect (if the chromosome in question has no imprinted genes). On the other hand, the presence of imprinted genes may result in significant clinical phenotypes, such as Angelman and Prader-Willi syndromes for Chr. 15.

Question 90

___ disease. A Clotting disorder that can be treated using recombinant factor IX

Answer 90

Christmas

Question 91

An individual version or genetic variant at a particular locus.

Answer 91

Allele

Question 92

Vertical (parent to child) inheritance of a disorder is typically seen for autosomal …… conditions.

Answer 92

Dominant

Question 93

An individual heterozygous for a recessive mutation

Answer 93

Carrier

Question 94

…… blotting is a technique sometimes used to look for the large DNA triplet repeat expansions that cause fragile X syndrome

Answer 94

Southern

Question 95

This type of enzyme copies DNA sequences as part of many laboratory genetic methods.

Answer 95

Polymerase

Question 96

In this pattern of inheritance, only mothers transmit the affected gene.

Answer 96

Mitochondrial

Question 97

An aspect of family structure that increases the risk of autosomal recessive disease.

Answer 97

Consanguinity

Question 98

That part of a gene whose sequence is represented in the mature mRNA.

Answer 98

Exon

Question 99

This syndrome, inherited as an autosomal dominant, can present with dislocation of the lens of the eye.

Answer 99

Marfan

Question 100

This term is used to refer to increasing severity of an inherited disease as it passes down successive generations.

Answer 100

Anticipation

Question 101

A …… nucleotide causes chain termination during DNA sequencing.

Answer 101

Dideoxy

Question 102

This type of endonuclease cleaves DNA at specified positions, determined by the nucleotide sequence.

Answer 102

Restriction

Question 103

A USA city whose name is given to a leukaemia-causing chromosomal rearrangement.

Answer 103

Philadelphia

Question 104

A term used to describe how a genetic change manifests itself.

Answer 104

Phenotype

Question 105

Scientist who discovered the process of X chromosome inactivation.

Answer 105

Lyon

Question 106

Centromeric DNA repeat family.

Answer 106

Alphoid

Question 107

A gene copy that has acquired inactivating mutations

Answer 107

Pseudogene

Question 108

The sugar component of the DNA backbone

Answer 108

Deoxyribose

Question 109

A genetic __?__ results in reduced diversity

Answer 109

Bottleneck

Question 110

This type of mutation results in an amino acid substitution

Answer 110

Missense

Question 111

A short, non-coding regulatory RNA species

Answer 111

MicroRNA

Question 112

A type of mutation commonly underlying haemophilia A

Answer 112

Inversion

Question 113

This type of simple tandem repeat is commonly used for genetic fingerprinting

Answer 113

Microsatellite

Question 114

Stretches of this amino acid are encoded by the trinucleotide repeats involved in some neurodegenerative disorders (e.g. Huntington's)

Answer 114

Glutamine

Question 115

A splice ___ site is found at the 5' bounday of all but the first exon in a gene

Answer 115

Acceptor

Question 116

Common neurological disorder in people with Down Syndrome

Answer 116

Dementia

Question 117

Stage of cell cycle at which chromosomes can be seen microscopically

Answer 117

Metaphase

Question 118

Any deviation from the normal balance chromosomal complement is termed ____

Answer 118

Aneuploidy

Question 119

DiGeorge syndrome is a common deletion on which chromosome

Answer 119

22

Question 120

The MYCN oncogene is characteristically amplified in this childhood tumour

Answer 120

Neuroblastoma

Question 121

Method for detecting a single chromosomal loci in metaphase of interphase cells

Answer 121

FISH

Question 122

Type of genome-wide genetic study based in a population, rather than examining inheritance in families.

Answer 122

Association

Question 123

A congenital disorder caused by recurrent deletion of part of Chr. 22q11

Answer 123

DiGeorge

Question 124

What is OMIM?

Answer 124

Internet catalogue of genes and single-gene inherited disorders

Question 125

What is DECIPHER?

Answer 125

Database of human chromosomal variation and it's clinical effects. A patient's genomic variation can be compared to those of a large number of deposited cases

Question 126

This tissue is typically sampled from 10 weeks gestation onward for prenatal diagnosis.

Answer 126

Chorionicvillus

Question 127

The ___ body is a condensed inactivated X chromosome visible in the nucleus of female cells

Answer 127

Barr

Question 128

True or false: Expression of imprinted genes is generally monoallelic

Answer 128

True