Unit 2 Flashcards
(52 cards)
T/F: Number of crossovers is directly proportional to distance between gene loci
True (AH Sturtevant)
.378 % recombinants would be how many MUs?
37.8 MUs, or 37.8 cM
Who’s lab showed linkage experiments in Drosophilia support cmsm theory of inheritance?
TH Morgan
genes are linked through generations-no random mixing
Genes are arrayed in a linear order along the length of a chromosome.
Homologs carry the same array of gene loci, but not necessarily the same alleles
Evidence that crossing-over in one area can decrease the likelihood of an exchange in an adjacent area
interference
if genes are located far apart on the same chromosome, what would we expect RF to be?
50%
A 4:4 pattern indicates RECOMBINATION/NO RECOMBINATION has occurred between the centromere and the gene in question
No Recomb
A 2:2:2:2 pattern or a 2:4:2 pattern indicates RECOMBINATION/NO RECOMBINATION has occurred between the centromere and the gene in question…
Recomb
When two pairs of alleles are segregating, how many asci patterns are possible…
3
T/F: If A and B loci are linked, PD»NPD
True
In 1936, who demonstrated somatic cell crossing over during development
Studied the X-linked genes yellow and singed
y+ sn/y+ sn females x y sn+/Y males
(singed females x yellow males)
Curt Stern
What could produce the mosaic pattern seen in the flies?
chromosomal nondxjt or chromosomal loss during mitosis
adjacent patches of both yellow cuticle and signed bristles (twin spots) could only arise if…
both patches of mutant tissue arose from the same event…crossing over during mitosis
name this protein important to cell cycle control which supresses tumors
Rb protein, a tumor supressor gene
loss of Rb protein/inactivation free what?
EF2, stimulates proliferation
T/F: Heterozygotes for an RB gene mutation are at increased risk of retinal cancer…
True
The gene for the enzyme superoxide dismutase II is located at band 1 in region 2 on the long arm of chromosome 6. This would be abbreviated
6q21
In analyzing a human karyotype:
a) test results can be obtained in several hours, using mitotic cells taken directly from blood; b) all chromosomes are easily identified simply on the basis of size and centromere position; c) colchicine is added to arrest cells in metaphase; d) all of the above; e) none of the above.
C
The successful mapping of a gene to a human chromosome by somatic cell hybridization requires that:
a) the parental cells will be preferentially killed in a selective media; b) human chromosomes are randomly lost from the hybrid cells; c) the human gene products can be identified in hybrid cells; d) all of the above; e) none of the above.
D
In Neurospora, a first division segregation pattern:
a) represents a single crossover between a gene and the centromere; b) identifies a recombinant ascus; c) will produce non-parental ditype asci; d) all of the above; e) none of the above
E
True or false. The Delbruck-Luria fluctuation test is a probability technique designed to aid in assembling linkage information from human pedigree data.
True or false. In most organisms, mutation rates are harder to measure than mutation frequencies.
False
True
The idea that genes control the ability to produce enzymes was first suggested from observations in which organism?
a) pea plants; b) fruit flies; c) E. coli; d) mice; e) humans.
E
True or false: All genes located on the same chromosome must be within 50 map units of one another.
false
What is important to know about this question?
A geneticist crosses two yellow mice with straight hair and obtains the following progeny: ½ yellow, straight; 1/6 yellow, fuzzy; ¼ agouti, straight; 1/12 agouti, fuzzy. This cross indicates:
YY are never born. YY is recessive lethal, so yellow mice are obligate heterozygotes Yy
If a cmsm has arms of equal length is is termed?
metacentric
