Midsem test - topic 1 Flashcards

Question

Minisatellites

Answer 1

longer repeats which doesnt code for proteins (15-100bp)

Answer 2

- mobile DNA sequences - can insert themselves into many different locations in the genome

Answer 3

- composed of tandem arrays - sequence = TTAGGG

Answer 4

probe chromosome with short sequence of fluorescent ssDNA that binds via complementary base pairing, ssDNA finds homologous chromosomal region during hybridisation

Answer 5

physical and functional unit of heredity

Answer 6

specific place where a gene is located

Answer 7

different versions of the same gene

Answer 8

paired chromosomes with same gene sequence and loci but may differ in alleles

Answer 9

- in somatic cells - one cell division results in 2 daughter cells - chromosome number maintained - one S phase per cell division - no pairing of homologs - no crossover - centromeres divide at anaphase - conservative - can be diploid or haploid

Answer 10

- cells in sexual cycle - 2 cell divisions resulting in 4 cells - chromosome number is halved - one S phase for both divisions - full interaction of homologs at prophase 1 - atleast 1 crossover per homolog during prophase 1 - centromeres divide at anaphase 1 - promotes variation - cells

Answer 11

9:3:3:1 = independent assortment/unlinked

Answer 12

found close together so they have a decreased chance of crossover/recombination

Answer 13

- involves crossing a heterozygous individual with homozygous recssive

Answer 14

dominant allele on different homolog, has decreased recombination

Answer 15

dominant allele on the same homolog, increased recombination

Answer 16

genes on different chromosome so recombination occurs via independent assortment during anaphase

Answer 17

recombination of genes on the same chromosome

Answer 18

it gets closer to 50% but cannot become more than 50% as only 2 sister chromatids are involved

Answer 19

- includes double crossovers - allows the order of genes to be determined - produces 2 parental and 6 recombinant progeny

Answer 20

- occurs when expected frequency is not equal to the observed - one crossover is inhibiting the other crossover - when I = 1 there is complete interference

Answer 21

- haploid fungi (n=7) - asexually and sexually - has 2 identical looking mating types which can be regarded as simple sexes - one of the first model organisms

Answer 22

- when 2 different mating types come into contact their cell walls and nuclei fuse to form a diploid nuclei - perithecia forms which contain asci - diploid nuclei undergoes meiosis to produce 8 ascospores in one long asci - each meiocyte produces a linear array of 8 ascospores

Answer 23

crossover hasnt occured - 4:4 pattern

Answer 24

crossover between gene and centromere - 2:2:2:2 pattern

Answer 25

centromeres attaching to the spindle at random during the 2nd meiotic division

Answer 26

(recombo/total x100) / 2 - HAVE TO DIVIDE BY 2 AS ONLY HALF OF THE PRODUCTS OF ANY MEIOSIS WITH A SINGLE CROSSOVER WILL BE RECOMBINANT

Answer 27

- crossing over involves breakage and reunion of non-sister chromatids at the 4 chromatid stage - chiasmata = sites of crossing over

Answer 28

- shows actual location of genes - good resolution and accurate - sequence based - gene loci determined - sources = somatic cell hybrid mapping and genome sequencing

Answer 29

- created from recombination frequency data - limited accuracy - gene order and relative position determined - source = recombination analysis of phenotypic and molecular markers

Answer 30

inability to perform a testcross and humans have a small number of progeny

Answer 31

- first human chromosome mapped - suitable for mapping by recombination analysis because males are hemizygous

Answer 32

- human and mouse somatic cell hybrids = different human chromosomes will be lost in different cell lines - FISH = fluorescent hybridisation, tags chromosomes - molecular markers = map gene of interest to a molecular marker

Answer 33

- deletion - duplication - inversion - translocaion

Answer 34

- usually requires 2 chromosomal breaks - results in the absence of a centromere - terminal = at end - interstitial = within chromosome arm - intragenic = small deletion within a gene that inactivates the gene - multigenic = involve several genes, creates dosage problem - in meiosis chromosomes with deletion will form a loop to account for the loss

Answer 35

- tandem = adjacent, inserted next to duplicate - insertional = located elsewhere in genome - a diploid cell with a duplication with have 3 copies which causes a dosage issue - effective for increasing the number of copies and size - to detect a duplication look at banding patterns and presence of loops at meisosi

Answer 36

- involve 2 chromosome breaks in same chromosome, region is flipped then reinserted - paracentric = centromere is outside the inversion - pericentric = centromere is inside the inversion - dont change the amount of genetic material - has to have 1 centromere and 2 telomeres to survive - acentric chromosome = lacks a centromere so it will not segregate in anaphase - inversion loop forms during meiosis to pair with homolog

Answer 37

- involves movement of genetical material between non-homologous chromosomes or within the same chromosome - reciprocal = part of one chromosome is exchanged with one another - non reciprocal = part of one chromosome moves to another without exchange - can result in hybrid genes - chimps have more chromosomes due to translocation and loss of chromosome

Answer 38

- human chromosome 2 is metacentric with G-banding patterns that match 2 acrocentric chromosomes in chimps - human chromosome 2 has end to end fusion of 2 chromosomes

Answer 39

- euploidy - aneuploidy

Answer 40

- change in number of sets - common in plants = polyploidy - major mechanism by which new plant species have evolved - increased chromosome number = increased cell size - autopolyploid = sets from one species - allopolyploid = sets from 2 or more species that are closely related and partly homologous

Answer 41

- change in number of individual chromosomes - can arise in chromosome is lost if centromere is deleted, small chromosomes generated by translocations are lost, gametes arise from nondisjunction due to failure of seperation

Answer 42

- happens in humans but most die in utero - monosomy = 2n-1, non viable except turners chromosomes - trisomy = 2n + 1, viable in 21 (down syndrome),13,18 and sex chromosomes

Answer 43

genetically distinct cells within an organism that are derived from a single zygote - at birth = nondisjunction - later in life = alterations

Answer 44

genetically distinct cells within an organism that are derived from multiple zygotes - birth = fusion of 2 zygotes - later in life = transfusion of donor cells

Answer 45

- chromosomal = sex determined by genes located on the sex chromosomes - genes - environment

Answer 46

number of copies in a gene present in a genome

Answer 47

- XO = sterile female - aneuploidy

Answer 48

XXY = sterile male - anueploidy

Answer 49

- responsible for maleness - encodes for a transcription factor - protein binds to DNA and stimulates transcription of other genes which promotes development of testes - turns on SOX 9 - SOX 9 cooperates with other genes to activate expression of AMH - determined genetically and hormones

Answer 50

mutation on gene for androgen receptor on the X chromosome, embryo develops as female

Answer 51

- inactivated X chromosome - stable through mitosis but reactivated for meiosis in those that give rise to ova - inactivation involves modification of DNA and histones - multiple copies of RNA product of XIST attach and inactivate X - females arent that affected by X linked diseases due to the 2 copies of X

Answer 52

- mosaic of 2 type of cells = active X derived from male and active X derived from female - occurs early in development

Midsem test - topic 1 Flashcards

(76 cards)