Term
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Definition
• Brightly stained thread like structures observed
microscopically in the nuclei of plant and animal
cells.
• Each species has a characteristic number, usually in
matched pairs, except of the sex chromosomes. |
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Term
Chromosomes are cellular entities responsible....
Example |
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Definition
for
transmitting the genetic information from parent to
offspring.
• Genetic content as well as dosage important: e.g.
Down syndrome. |
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Term
Genes are located on Chromosomes
• Early observations:
– Microscopic visualization of_____ , and
movement of_____ within gametes.
– Evidence that nucleus of gametes played an
important role in ______ and ______formation.
– Fertilization was recognized as a...
– Linkage of sex of an organism with ...
– Chromosomal movements mimicked behavior of
genes as per... |
|
Definition
-gametes, chromosomes
-fertilization, zygote
-fusion of male and
female gametes
-sex
chromosome type
- Mendel’s laws. |
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Term
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Definition
-female (Turner)
-male
(Kleinfelter |
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Term
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Definition
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Term
Birds
: female =
; male = |
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Definition
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Term
Fertilization: During gamete formation, germ cells
undergo _____to generate ______; this accounts for
the ______ of genes as proposed by Mendel. |
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Definition
| -Meiosis, gametes, segregation |
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Term
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Definition
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Term
• When male and female gametes reunite, the resulting
fertilized egg is . |
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Definition
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Term
• The fertilized egg has a full complement of ______, and gametes come together obeying
Mendel’s law of _______ |
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Definition
| paired chromosomes, independent assortment |
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Term
• Cell division during subsequent embryonic
development and in adult organisms occurs via _____,
when total genetic information is _____ before it is
split up into________ |
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Definition
| Mitosis, doubled, individual daughter cells. |
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Term
In 1903,_______proposed that chromosomes
carry the hereditary units described by Mendel. |
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Definition
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Term
Evidence of Inheritance of genes correspond with chromsomes:
– Two copies of....
– Total chromosome #... |
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Definition
-chromosomes and hereditary units.
-maintained in every generation. |
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Term
– Chromosomes assort at ______of the
others.
Evidence of Inheritance of genes correspond with chromsomes:
– Gametes have half the number of chromosomes: |
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Definition
-each pole independently
-one each
rather than a pair of each. |
|
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Term
Evidence of Inheritance of genes correspond with chromsomes:
– At fertilization, the two gametes fuse...
– In cells derived from the fertilized egg... |
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Definition
-causing the
chromosomes to pair up again.
half the chromosomes
are from the father, and half are from the mother: similar to
hereditary material. |
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Term
Thomas Morgan attempted to correlate
transmission of a specific trait with
transmission of a specific chromosome:
– Trait:
– Chromosome:
– White-eyed male crossed to pure bred red eyed
female. (Cross A). F1 ...
– Self cross of F1 (Cross B): |
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Definition
-Drosophila eye color
-X-chromosome (sex-linked
transmission).
-were all red eyed.
-F2 females were all
red eyed, but males were ½ red, ½ white eyed |
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Term
Morgan's cross C
Cross C: a cross between the white male
from F2 and the red-eyed (heterozygous)
female from F2: Offspring are 50% red eyed,
50% white-eyed....
(analogous to a test cross) |
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Definition
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Term
Cross D: a cross between a white eyed
female and a red eyed male:
• Crosses C and D are |
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Definition
-all females were
red eyed, all males were white eyed.
(crisscross inheritance).
-reciprocal crosses |
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Term
Morgan's cross
Data do not obey typical Mendelian
inheritance pattern since males and females
are not transmitting traits equally:
– Reciprocal crosses are not ____
– ___ inheritance |
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Definition
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Term
– Morgan hypothesized that the gene/allele
causing white eyes was on the...
– Males carried only one X chromosome: they were_______for the eye color gene. |
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Definition
- X-chromosome.
-hemizygous |
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Term
Nondisjunction:
– Morgan’s student, Calvin Bridges, repeated Morgan’s
crisscross inheritance experiment on a much larger scale. |
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Definition
– Most females were red eyed; mostmales were white eyed.
– A few white-eyed female offspring resulted. |
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Term
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Definition
He hypothesized that this was because of a mistake in
meiosis caused by improper separation of the X
chromosome. |
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Term
– Bridges analyzed the chromosome content of the white
eyed females.. |
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Definition
and indeed found that these flies had one extra X, confirming his hypothesis. (remember, in flies,
XXY is a female, not a male) |
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Term
| X-linked recessive traits: |
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Definition
– Incidence much higher in males
– Never passes from father to son; father may
pass on bad allele to all daughters, making them
carriers.
– Often appears to skip a generation.
– Carrier females transmit to sons with 50%
probability; daughters have 50% probability of
becoming carriers.
Colorblindness, hemophilia |
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Term
| X Linked dominant traits in Humans |
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Definition
– Affected males produce all affected daughters and no
affected sons.
– A heterozygous affected female will transmit the
disease to half her children, males and female offspring
being equally affected.
– On an average twice as many females as males are
affected: females have two alleles, either may be
affected, therefore twice the probability.
• Example: Hypophosphatemia: a disorder causing
vitamin D resistant rickets. |
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