5. Neurogenetics Flashcards by Em Brocklesby

Genetics is the scientific study of i____ v___: of how traits are p____ d____ through g____, and the role of g____ in determine those traits

inherited variation
passed down, generations
genes

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Cells are the basic b____ b____ of all l____ things

building blocks, living

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Chromosomes are found i____ your cells. A chromosome is a t____ w____ c____ of DNA

inside, tightly wound coil

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DNA s____ make up genes

segments

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Genes are long sequences of b____ p____ in the DNA that e____ p____

base pairs, encode proteins

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Your genes are an i____ m____ for your body

instruction manual

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there are approx ____ genes on human chromosomes

23,000

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Each gene carries i____ that determine your f____/t____, such as eye colour, hair colour and height

instructions, features/traits

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Humans have __ pairs of chromosomes and __ base pairs of DNA

23, 3 billion

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DNA stands for d____ a____ and contains 3 parts:
1. N____-containing b____
2. F____-c____ s____
3. P____ group

deoxyribonucleic acid
1. Nitrogen-containing base
2. Five-carbon sugar
3. Phosphate group

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Humans share over __% of our DNA sequence with each other

99.9%

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Natural variations in our DNA are known as s____ n____ p____ (SNPs)
Around __ SNPs identified through human genome project sequencing.
The unique combination of SNPs that we i____ from our parents are responsible for the genetic component that makes us d____ to one another

single nucleotide polymorphisms
~ 3,300,000
inherit, different

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Mitosis cell division happens in s____ cells and daughter cells are i____ to parent cell

somatic, identical

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Meiosis cell devision happens in g____ and daughter cells contain h____ the number of chromosomes

gametes, half

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Meiosis:
1. H____ r____ or “crossing over”
2. Allows g____ d____
3. Offspring all share __% of each parental genes, but a different __%

Homologous recombination
genetic diversity
50%, 50%
(natural selection and evolution)

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A gene is expressed through the processes of t____ and t____

transcription, translation

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During transcription, the enzyme, the enzyme R____ p____ uses DNA as a template to produce a p____-m____ t____. The p____-m____ is processed to form a mature m____ molecule that can be t____ to build the protein molecule (p____) encoded by the original gene

RNA polymerase
pre-mRNA transcript
pre-mRNA , mRNA
translated
polypeptide

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Transcription is in the n____, the gene’s DNA sequence is c____ into m____ R____

nucleus
copied
messenger RNA (mRNA)

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Translation is where a r____ attaches to the m____ and moves along the m____, reading each t____ codon (3 bases) and using t____ R____ to put together the a____ a____ chain to make a p____

ribosome
mRNA
mRNA
triplet
transfer RNAs (tRNA)
amino acid
protein

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Mendel’s law (Mendelian Inheritance):
1. Gregor Mendel (1865) - inheritance through “t____ u____”
2. Height in peas - d____ trait (tall or short, no i____
3. Trait that is controlled by a s____ g____ in one or two forms (a____)
4. A____ = v____ of a gene
5. __ copies of the gene in each parent pea, __ copy is carried to each of the offspring - with tall (__) or short (__)
6. Height - Tall (__) is d____, short (__) is r____
7. When c____-f____ all the first generation (F1) offspring are t____
8. But short character reappears in the second generation (F2) in just a q____ of the offspring

transmissible units
dichotomous, in-between
single gene, alleles
Allels, variants
2, 1, TT, tt
T, dominant, t, recessive
cross-fertilised, tall
quarter

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Mendel’s law:
1. Law of s____ - each individual has two a____ of a gene, one from each parent. These a____ s____ during reproduction, so each g____ gets only one
2. Law of I____ A____ - genes for different traits are inherited i____ of each other (unless they are linked on the same chromosome)
3. Law of D____ - some alleles are d____, while others are r____

segregation, alleles, alleles segregate, gamete
Independent Assortment, independently
Dominance, dominant, recessive

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Genotype = g____ i____

genetic information

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Phenotype = how it displays… o____ p____ traits (interaction of g____ with e____)

observable physical, genotype, environment

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Alleles = v____ of g____

variants of genes

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M____ in the genetic sequence can lead to d____

Mutations, disorders

Gene variations/mutations can affect f____ or e____

function (coding sequence e.g. Huntington's) expression (non-coding, regulatory sequences)

Huntington's Chorea is d____ inheritance. It is an inherited disorder that causes n____ cells in parts of the brain to g____ b____ d____ and d____. The disease attacks areas of the brain that help to control v____ movements. People living with HD develop u____ dance-like movements and a____ body postures, as well as problems with b____, e____, t____ and p____

dominant, nerve (neurons), gradually break down, die, voluntary, uncontrollable, abnormal, behaviour, emotion, thinking, personality

Huntington's Chorea is a single gene disorder on chromosome __

Autosomal dominant inheritance = a s____ copy will be dominant and lead to the disease

Autosomal dominant inheritance: single copy will be dominant and lead to the disease (if 1 parent has Huntington’s, 50% of the offspring will develop Huntington’s).

Phenylketonuria is r____ inheritance. It is a mutation in the PAH gene (phenylalanine hydroxlase (PAH)) - e____ that breaks down d____ p____. If PKU is not treated, p____ can build up to harmful levels in the body, causing i____ d____, b____ d____ and e____. Build up of p____ is toxic to d____ brain. PKU is s____ for at birth in the UK, as symptoms can be prevented by d____

recessive enzyme dietary phenylalanine phenylalanine intellectual disability, behavioural difficulties, epilepsy phenylalanine, developing screened, diet

Monosomy = s____ copy of a chromosome. E____ l____ (e.g. c____ d____ c____ syndrome)

single embryonic lethal cri du chat

Trisomy = t____ copies of a chromosome. Very high rate of e____ l____ (e.g. d____ syndrome)

three, embryonic lethality, downs

Downs syndrome is trisomy in chromosome 21 and leads to smaller brain size of f____ l____ and c____, mild to moderate i____ a____ and high risk of early onset A____ d____. Symptoms narrowed down to __-__ genes on chromosome 21

frontal lobe, cerebellum intellectual ability Alzheimer's Disease 20-40

The wrong number of chromosomes impacts normal development reflecting importance of g____ d____

gene dosage

Y chromosome has very few genes mostly governing male s____ f____. X chromosome has many genes that play v____ role in both s____

sexual function vital, sexes

X i____ in females switches off one copy of X chromosome during e____

inactivation, embryogenesis

X-linked disorders vary in their p____ according to s____

penetrance, sex

X-i____ ensures that the d____ of a____ genes is maintained in all individuals

inactivation, dosage, active

Female mammals t____ s____ one of their two Xs in a complex and highly c____ manner (Lyon, 1961). The inactivated X chromosome then c____ into a compact structure called a B____ b____, and it is stably maintained in a s____ state (Boumil & Lee, 2001)

transcriptionally silence, coordinated condenses, Barr body, silent

An adult female is a mosaic of c____ derived from different e____ cells. Within a clone, all the cells inactivate the s____ X, but between clones the choice is random. If she happens to be a c____ of an X-linked r____ disease, this can have major implications

clones, embryonic, same, carrier, recessive

Huntington's Disease: 35 or more C__ repeats on a mutated H____ gene on chromosome __ leads to n____ d____ which leads to a____ of b____ g____ and e____ of l____ v____

CAG, HTT, 4, neuron degeneration, atrophy, basal ganglia, enlargement, lateral ventricles

Rett syndrome: 1. Progressive n____ disorder almost e____ affecting f____, leading to profound d____ 2. Rare condition - 1 in __ 3. Mutation in the gene M____ - this "t____ r____" turns off the e____ of unwanted genes during s____ f____ 4. X-l____ 5. S____ mutation rather than i____ 6. X-i____ means that not all cells will express mutated M____ gene, therefore v____ p____, sometimes see m____ symptoms 7. Affected males do not have a "g____ c____" of M____ - much more severe p____, e____ l____ or die soon after b____

1. neurodevelopment, exclusively, females, disabilities 2. 10,000 3. MeCP2 (methyl CpG binding protein 2), "transcriptional repressor", expression, synapse formation 4. X-linked (gene on the X chromosome) 5. Spontaneous, inherited 6. inactivation, MeCP2, variable penetrance, milder 7. "good copy", MeCP2, phenotype, embryonic lethal, birth

Fragile X (X-linked): 1. Most common i____ form of l____ d____ 2. Relatively c____ 3. X-linked - symptoms predominantly in m____ 4. Mutation in 5__ end of the F____ gene, consisting of an a____ of a C____ repeat 5. The F____ gene encodes the F____ protein, which is thought to shuttle select m____ between c____ and n____ 6. Milder penetrance in f____ due to X-i____, so not always recognised

1. inherited, learning disability 2. Common (1 in 4000 males; 1 in 6000 females (carrier of ‘premutation’: 1 in 259 females; 1 in 800 males)) 3. males 4. 5'UTR, FMR1gene (fragile X messenger ribonucleoprotein 1), consisting of an amplification of a CGG repeat (200+ copies; normally between 6 and 40 repeats). 5. FMR1, FMR, mRNAs, cytosol, nucleus 6. females, inactivation

Epigenetics is the study of how cells c____ g____ a____ without changing the DNA sequence. Epigenetic changes are m____ to DNA that regulate whether genes are turned o____ or o____. These modifications are attached to DNA and do not change the s____ of DNA building blocks

control gene activity, modifications, on, off, sequence

Epigenetic mechanisms are affected by: 1. D____ (in u____ and c____) 2. Environmental c____ 3. D____/p____ 4. A____ 5. D____

1. Development (in utero, childhood) 2. chemicals 3. Drugs/pharmaceuticals 4. Aging 5. Diet

DNA methylation - Methyl groups can t____ DNA and a____ or r____ genes

tag, activate, repress

Histones are proteins around which DNA can w____ for c____ and gene r____

wind, compaction, regulation

Histone modification - the binding of epigenetic factors to h____ "t____" alters the extent to which DNA is w____ around h____ and the a____ of genes in the DNA to be a____

histone "tails", wrapped, histones, availability, activated

Epigenetic modifications can be s____ through the life course, but some are affected by the e____. There is early development influence on s____ r____ and d____ in later life. Studies found an effect of m____ care in mice on the e____ r____ of the expression of Nr3c1, the gene that encodes the g____ r____. Absence of licking lead to promoted m____ and low levels of G____ r____ M____ retained through lifetime. Without G____ r____, there was loss of f____ in HPA axis, increased s____ hormones and increased a____/d____

stable, environment stress resilience, depression maternal (specifically of licking and grooming pups), epigenetic regulation, glucocorticoid receptor (GR) methylation, glucocorticoid receptors Methylation, GR, feedback, stress, anxiety/depression

E____ influence on p____ can affect o____. Disrupted histones in s____ cells: Showed altered R____ profile in o____ (and g____-o____) Histones can be modified by c____ (e.g. smoking, drinking)

Environmental, parents, offspring sperm RNA, offspring, grand-offspring chemicals

The unique combination of Single Nucleotide Polymorphisms (SNPs) we inherit from our parents are responsible for the g____ c____ that makes us d____ to one another

genetic component, different

Gene association studies: 1. GAS look for sorting of SNPs in c____ genes 2. Genome wide association studies (GWAS) look for what SNPs sort with d____ state

1. candidate 2. disease

Mutations in PSEN1, PSEN2 and a____ p____ p____ (APP) cause Alzheimer's disease. They are all on chromosome __ (D____ t____)

amyloid, precursor protein, 21, Down's trisomy

Alzheimer's disease is associated with the build up of a____ b____ p____ in the b____

amyloid beta plaques, brain

Risk of AD has been associated with SNP difference in APOE_ (c____ a____) and APOE_ (changes an a____ a____ in protein)

APOE3 (common allele) APOE4 (amino acid)

Concordance = the degree to which a trait is seen in __ individuals. Concordance rates in twins show that Huntington's disease is p____ g____ whereas Schizophrenia and bipolar disorder and p____ and e____

purely genetic polygenetic and environmental

In a study of genetics of schizophrenia, it was found that there was a __8% concordance rate in MZ twins and a __7% concordance rate in DZ twins. This shows there is a large g____ c____, but not p____ g____

48%, 17%, genetic component, purely genetic

In a GWAS of over 150k people (36,000 with schizophrenia), they found __ schizophrenia-associated genetic loci. These genes included ones associated with s____ t____, g____ and d____

108 synaptic transmission, glutamate and dopamine (Dopamine D2 receptor)

Advantages of animal studies include: 1. S____ of genes and biological f____ with humans 2. C____ of behaviour with humans 3. Create i____ strains of animals that are g____ i____ 4. Control e____ conditions 5. M____ genes: m____ or r____ particular gene, or i____ copy of a human gene

1. Similarity, function 2. Conservation 3. inbreed, genetically identical 4. environmental 5. Manipulate, mutate, remove, insert

Advantages of genetic studies of mice: 1. C____-effective culturing and handling 2. Can easily be b____ in the lab 3. Short l____ c____ 4. Genetic t____ and well u____ genetics 5. Similarity to human biology and d____ m____ 6. Amenable to e____ m____

1. Cost 2. bred 3. life cycle 4. tractability, understood 5. disease manifestation 6. experimental manipulation

Synteny between human and mouse chromosomes: 1. Human chromosome 1 - mouse chromosomes __ and __ respectively, with a small bit on chromosome __ 2. The long arm of chr 21, which includes d____ s____ c____ r____, occurs intact on mouse chromosome __ 3. The X and Y chromosomes of the two species are almost entirely h____

1. 1, 4, 8 2. downs syndrome critical region, 16 (mice can therefore serve as a useful animal genetic model of Down Syndrome.) 3. homologous (as expected because the basic sex-determining genetic mechanisms is shared by all mammals)

I____ strains of mice will have different genetics, neurobiology and behaviour. Comparison of these strains can tell us about how g____ influence b____

Inbred, genetics, behaviour

Three genetically engineered mouse models: 1. K____ - functionally d____ a gene 2. K____ - introduce a s____ m____ 3. T____ - multiple copies of e____ DNA

1. Knockout, delete 2. Knockin, specific mutation 3. Transgenic, exogenous

5. Neurogenetics Flashcards

(63 cards)