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132 Cards in this Set

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Hybrid seeds
One that will produce off spring of more than one phenotype
Mendel's 1st Law
Each transmit is contributed by particulate factors that occur in pairs. Gamete formation=factors separate so each gamete recieves only 1 of each pair. Fertilization=double number restored.
Test cross
crossing to the recessive
reciprocal cross
both male and female get to be the parent of the tested species
Result of test cross if it's heterozygous?
1:1
Gene
One of Mendel's factors
allele
alternate form of a gene
gamete
sex cell: plant=pollen/ovule; animal=sperm and egg
zygote
formed by the fusion of 2 gametes
homozygote
carry identical alles of a gene
heterozygote
carry different alleles of a gene
genotype
genetic make up of an individual that is a description of carrried alleles
Phenotype
the trait determined by the phenotype
Mendel's 2nd law
independent assorment. The segregation of each gene pair during gamete formation is independent of all others
What happens when dominance is not general
You get an intermediate of the 2 parental phenotypes
What happens when multiple alleles are possible?
You get more than 2 phenotypes of 1 trait
How do you figure out if alleles are of the same gene?
test cross. If you get a 1:1 raio you know the alles have segregated from one another during gamete formation
What happens if several genes affect the same character?
You get a distorted Mendellian ration. It is usually a case of epistais.
What is the order for an epistatic pathway?
middle number to smallest number to biggest number
Pleitropy?
The production of superficially unrelated affects by one allele
What is the difference btwn pleitropy and several genes affecting the same character?
in pleiotropy, only one gene is involved, but it affects different traits.
Why does the ch gene in cats affect both the cat's color and crossed eyes?
The albino gene is related to melanin, which is relaated to the nuerotransmiter dopnanine
What is Wardenberg syndrom?
deafness, white forehead, and different eye colors in humans.
When are some alleles lethal?
when homozygous. Often expect a 1:2:1 genotpyic ration but instead you get a 2:1 ratio.
Esential gene
a gene that is leathal when homozygous
2 reasons that some alleles don't have constant effects on phenotype
environmental factors (temp, nutrition, disease, and age) and Genetic variation
Penetrance
% of cases where alleles affect their carrier
Expressivity
extent to which phenotype shows in affected individuals
Addition rule
P=P(A)+P(B) if a& b are mutually exclusive (either a or b)
Multiplication rule
P=P(A)xP(B) if they are independent events (A followed by B)
0!?
1
when to youse the binomial formula?
want to know the likelyhood that an event will occur, and it can occur in many different ways
What does it mean if the probability is 5% or less?
the data differ sifnificantly from expectation
What is fertilization?
the fusion of 2 cells
Does one sex cell (sperm or egg) contribute more to inheritance?
No, despite the fact that the egg is much bigger
What does the sperm contribute to the zygote?
a nucleus
What is a germ cell?
they give rise to gamates by migrating around the embryo to find the gonade. They then under go Meiosis
What are the 4 stages of Mitosis
Prophase, Metaphase, Anaphase, and Telophase
What is the number and type of cells yielded from Mitosis?
2 diploid cells
diploid?
2 chromosomes present in cell
haploid
1 chromosome present in cell
Prophase
1st stage of Mitosis, chromosomes condense in nuclear envelope
Are chromosomes constant w/ in a species?
Yes, and they occur in morphologically idetical pairs?
Metacentric?
centromere is in the middle
submetacentric
centromere is slightly off sides
accrocentric
centromere is dramaticallly off sides
telocentric
top/bottom leaves of chromatin doesn't exist
Metaphase
2nd stage of mitosis where nuclear envelope breaks down, the spindles form, and each chromosome attaches to the spindle by the centromere region. The are lined up along the metaphase plate of the spindle
Anaphase
3rd state of mitosis. Sister chromosomes move to opposite ends of the cell
Telophase
Spindle breaks down, nuclear enveopes reform around groups of chromatid at each end, creating 2 nuclei in one cell. Chromosomes decondense
interphase
when DNA is stained a chromatin can be seen
chromatin
meshwork of threads that the nuclei contains
Karyotype
view of chromosome sets at the end of prophase
what makes up the back bone of each chromatin
a long DNA molecue
what creates a harlequin chromosome
adding 5 bromo uracil during replication
What is a harlequin chromosome
one in which one side is half of "new" DNa and the other side is all old DNA
Germ/somatic cells
2 sets of homologs present in diploid form
gametes
only 1 set of homolougs/chromosomes present
diploid
only 1 set of homolougs/chromosomes present
what causes gametes to be haploid
meosis
Meosis
reductional division that reduces the chromosome # by 1
Bivalent
physical association of 2 homologs
Prophase I
chromosome condensation occurs.
Metaphase I
bivalents attach to the centromere @ the spindle. They line up @ the metaphase plate. The cetromeres orient to opposite poles
Anaphase I
homologs let go of one another and are moving to opposite poles
telophase I
chromosome condenses
Meisos II
equational division, no change in chromosome #
Prophase II
chromosome condensation, nuclear evelope breaks down, spindle forms, chromosomes attach
Metaphase II
???
Anapahse II
???
Telopahse II
nuclear envelope breaks down
how many cells/chromatid do you have to start w?
1 diploid cell w/ 2 chromatid
how many cells/chromatid do you have afer Meiosis 1?
2 haploid cells w/ 2 chromatid
how many cells/chromatid do you have afer Meiosis 2?
4 haploid cells w/ 1 chromatid
When do homologus chromosomes segregate>
during Meiosis 1
what fuse to gether to make a diploid zygote?
2 haploid gametes
What is the chromosome theory?
genes are on chromosomes
What did Elenor Carother's do?
she looked at grass hoppers at the chromosome w/ no homolougs segregated to both poles w/ a 1:1 ratio, showing that chromosomes sort independently
Wht did McClugh do?
Male grasshoper has an unpaired, accesory x chromosomee. Female have extra xx pair. Therefore x could be a se cell.
criss-cross inheritance
son looks like mother, daughter looks like father
Who worked w/ the fruit fly first?
thomas Hunt Morgan
sex chromosome
differ by sex
autosome
same in different sexes
What does it mean if the letter is capital in drisophila notation?
the variant is dominant
natro/patroclinus
have phenotype of the same sex parents
What is maldisjunction
When chromosomes that are supposed to go opposite ways go the same way, and therefore into one cell
What is an explanation for natro/patroclinus?
maldisjunction
What's the genotype for natroclinus?
xxx
Whats the genotype for patroclinus
xo
Which maldisjunctions can't survive?
xxx & 0Y
what determines the sex?
the number of xxx's
What role does Y have?
carrying the sperm
Hemizygous
present in only one copy
sex linked
located on a sex chromosome
christopher inheritance?
criss cross inhritance
In humans, X0
female, turner's syndrome-underdeveloped
In humans, xxy
feminized males, Klinfeld sydrom
in humans, xxx
normal fertil females
In humans x function? Y function?
feminizes; determines maleness (sex)
How does the Y determine sex in humans?
Y makes gonad become a testis, testis secrets androgens (testoterone), and andgrogens caus e the rest of genitalia/organism to be male
3 phases of sex-determination
1. gonadal sex-determined by Y
2. Formation of genetalia-by androgens
3. Puberty-androgens
TFM?
a gene that encodes the adrogen receptor, which are in the cells that androgen targets. In testicular femination, there is no receptor for androgens to bind to , so it's like androgens are not present. They look like females who don't go thru puberty
Which events of sex determination succeed during TFM? Which fail?
primary event; secondary and trieciary events fail
What gene on Y controls the primary phase of sex determination?
The Testis Determining factor (TDF)/Sex detrerming Region on the Y(SRY)
What has happened in xx individuals that are phenotypical males?
lacks TDF/SRY
What has happened in xy individuals that are phenotypically males?
TDF/SRY as moved
how can TDF be missing or moved?
Y encodes a small protein that is a transcription factor, which binds to regulatory regions of target genes, turning them on/off
Y linked
only males
Linkage
association of genes on the same chromosome
recombination
process of generating new gametic types (nonparental)
Recombination frequency
non parental gamete/total gametes times 100
cis(coupling)
alles on the same homoloug
trans (repulsion)
alleles on different homolougs
The recombination frequency between any 2 particular genes is...
a constant reproductie value btwn 0 & 50%
recombination frequency is porpotional to
physical distance apart
4 substages of prophase I
leptotene, zygotene, pachytene, diiptene & diakenesis
Leptotene
thin thread, condensation begins
chromomeres
bead like condensation
zygotene
paired thread-homogolus chromomeres apear, and chromosome pair during synapses
synapsis
progressive zipper like fashion in which chromosomes pair during pachytene
pachytene
thick tread-synapse is complete and chromosome is paired along the length
dipitene/diakenesis
two thread-homolougs apppear to try to repel each ohter, but the crhomatid hold the together
cohesive
glue that holds together sister chromosomes
Why is separation allowed during anaphase one?
cohesive glue is lost
how do we know Jansen's model is correct?
chromosome has to break in order for the harlequin chromosomes to form, which it does?
if 2 genes are far apart on the chromosome, what is more likely to happen?
a chaismid will fall between them
What did alfred sturdivant do?
he made a self-constitent map baseed on recombination frequencies
Autosmal recessive
1. males and females equal
2. found in siblings more than parents (risk of unborn sibling to affected individual=1/4)
3. often incest-related parents
4.appears isolated
Autosomal dominant
1. no generation skiping
2. equal in males in females
3. recurrence risk parent to child =1/2
X linked dominant
1. Never father to son
2. bad male x good female= all daughters bad
3. good male x bad female= 1/2 bad sons and 1/2 bad daughters
4. may be lethal in males
5. females more likely to be affected
X linked recessive
1. never father to son
2. males more likely
3. affected males get it from their mama
4.bad granpa-to carrier mom-to 1/2 bad sons
Y linked
only males