Term
| Historical Perspectives, examples of genetic diversity, Evolution, and artificial selection. |
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Definition
| -Wolves to dogs, edible plants from weeds, purposeful control over mating by choice of hardy plants, farm animals, etc, for breeding purposes. |
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Term
| Early misconceptions- one parent model |
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Definition
| a male parent contributes most of the offspring's inherited traits. |
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Term
| Early misconceptions- blended inheritance |
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Definition
| a mixing of traits from both parents occurs in offspring. |
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Term
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Definition
| an augustinian monk helped remove misconceptions with his work in pea plants in the 1840s-1870s. |
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Term
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Definition
| alternative forms of a given trait will have a systematic pattern of inheritance. |
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Term
| Heredity ________ apply equally to all _______ reproducing individuals. |
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Definition
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Term
| Pea Plants were chosen because, and pure breeding. |
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Definition
-Grew well in the area, fast turnover, lg sample size
-Male and Female organs on the same plant, ussually self-fert would give pure breeding offspring. |
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Term
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Definition
| easy to cross fertilize and manipulate as desired (offspring to parent). |
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Term
| Pea plants variance and traits. |
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Definition
| distinct, and independent |
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Term
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Definition
| reversing traits from male v. female parent. |
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Term
| Mendel studied these traits in peas. |
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Definition
| seed Color,seed shape, flower color, pod color, pod shape, stem length, and flower position. |
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Term
| Monohybrid cross, what Mendell observed |
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Definition
| Yellow is dominante, and green is recessive. In next generation, there is a ratio of 3:1 (y:g), reappearance of green peas which disproved blending hypothesis. |
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Term
| Discrete units of inheritance |
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Definition
| for each trait every plant carries two copies of the unit of inheritance. |
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Term
| Today the unit of inheritance is referred to as an ________. Each individual has two alleles for each ____ |
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Definition
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Term
| Mendel's Law of segregation |
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Definition
| The two alleles for each trait seperate (segregate) during gamete formation, then unite at random, one from each parent at fertilization. |
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Term
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Definition
| haploid gametes fuse to form diploid fertilized zygote. |
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Term
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Definition
| Each parent produces two gametes, one with each allele for a given gene. Using a square grid, one can represent all possible allele combinations when the gametes from parents fuse to form the zygote. |
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Term
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Definition
| Homozygous dominant yellow, heterozygous yellow, homozygous recessive green. |
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Term
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Definition
| The probability of two or more independent events occurring together is the PRODUCT of the probabilities of each individual event occurring itself. |
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Term
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Definition
| The probability of either one of the two independent and mutually exclusive events occurring is the SUM of their individual probabilities. |
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Term
| Law of Independent Assortment |
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Definition
| Genes for different traits assort independently of one another in the production of gametes. |
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Term
| Genotypic classes represent |
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Definition
| the four phenotypes seen. |
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Term
| 9 different genotypes fall into the |
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Definition
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Term
| Use__________ to predict dihybrid ratios |
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Definition
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Term
Multihybrid crosses: results could be
predicted |
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Definition
| based on rules of probability. |
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Term
| Multihybrid crosses Steps |
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Definition
– Separate individual traits and calculate
probability for each phenotype and genotype
for that trait.
– Combine the traits by applying law of product. |
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Term
| Limitations of Mendell's Laws |
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Definition
• Deviations from the predictions can occurs
because of chance variation.
• Probability works well with large sample
size; not so accurate with small sample size.
• Predictions are meaningful for a population,
not for an individual. |
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Term
| Limitations of Mendel's Law |
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Definition
• There are some instances of true deviation:
– When dominance relationships are not clear
– when Mendel’s laws of independent assortment
may not hold true |
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Term
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Definition
• Lack of pure breeding lines.
• Experimental mating not possible
• Repeat experiments not possible.
• Longer generation time.
• Fewer progeny.
• Total available progeny only fraction of all
possible genetic combinations: makes ratio
calculation hard |
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Term
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Definition
Basic method is observational rather than
experimental.
• Reconstructing past generation family histories.
• Pedigree construction is most important aspect of
observational analysis.
• Need large number of families; several
generations within a family.
• Patterns of inheritance, consistency with which
parents transmit to offspring; sex of affected
offspring, etc are important in deducing how trait
is transmitted. |
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Term
| Most traits are controlled |
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Definition
by multiple genes or complex
interactions between gene products and/or
environmental factors. |
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Term
| Most confirmed single-gene traits are |
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Definition
rare and involve
life-threatening disability, so are gradually eliminated
from the population. |
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Term
| Four broad types of inheritance patterns: |
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Definition
– Autosomal dominant
– Autosomal recessive
– X-linked dominant
– X-linked recessiv |
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Term
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Definition
| May have more than one mode of inheritance. |
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Term
| Autosomal dominate traits- How many parents of individuals are affected? |
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Definition
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Term
| Autosomal Dominate traits most affected individuals are ___? ___% chance of passing on a trait to the offspring. |
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Definition
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Term
| Autosomal Dominate traits are males or female affected? will two affected individuals always have an affected child? |
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Definition
| Both, nope two may have normal children, |
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Term
Autosomal dominate traits have a _____ pattern of inheritance. _____ may be more severely
affected than heterozygous individual |
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Definition
| verticle, homozygous dominate |
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Term
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Definition
Autosomal dominant.
• Prevalent in one of 10-20 thousand individuals
worldwide.
• Late onset disease.
• Intellectual deterioration, severe depression, jerky
irregular movements.
• Progressive deterioration of nerve cells.
• Children of an individual have a 50% chance of
having the same condition.
• Gene identified: Huntingtin; chromosome 4p. |
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Term
Autosomal Recessive Traits
• For rare traits, most affected individuals are....
• Parents are both carriers: risk is |
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Definition
| children of unaffected parents.25% |
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Term
•______children of two affected parents are
affected.• Males and females? |
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Definition
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Term
• In very rare traits, affected individuals may
be offspring of a _________ mating.
• ________pattern of inheritance. |
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Definition
| consanguineous, horizontal |
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Term
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Definition
• Prevalent in Caucasian populations at the rate of 1 in
2000, carriers being 1 in 25.
• Very rare in African and Asian populations.
• Disease of epithelial cells, where exocrine gland
secretion is abnormal.
• Pancreatic insufficiency with formation of cysts and
fibrous deposits.
• Chronic lung disease: blockage of lung airways with
sticky mucus.
• Sterility or reduced fertility prevents transmission of
disease to next generation.
• Gene is CFTR (chromosome 7q); regulates chloride ion transport |
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Term
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Definition
female, male– The presence or absence of Y makes the
difference between male and female.
– XO = female (Turner) , XXY = male
(Kleinfelter) |
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Term
Drosophilia XX = ; XY =
– The ratio of X to an ____ determines sex.
– ____ = sterile male, ____ = female |
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Definition
| female, female, autosome, XO, XXY |
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Term
| In Birds: female = ___; male = ___ |
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Definition
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Term
| Humans- XXY- _____, XO______ |
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Definition
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Term
| XXX in Drosophilia, in humans |
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Definition
| Dies, nearly normal female |
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Term
| XXY in drosophilia, human |
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Definition
| Normal female, Klienfelter male whose sterile, tall and thin |
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Term
| XO in drosophilia, humans |
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Definition
| Sterile male, tuner female sterile webbed neck |
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Term
| XXY in drosophilia, humans |
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Definition
| Normal male, nearly normal or normal male. |
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Term
| OY in drosophilia, humans |
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Definition
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Term
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Definition
| is x linked, on the x chromosome, males are hemizygous. |
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Term
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Definition
| One X and Y that doesn't have an allele X___ |
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Term
| X linked reciprocal crosses |
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Definition
• Eye color in drosophila is X linked
• On the X chromosome
• Males are hemizygous |
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Term
Red eyes in _____
allele
• Different ratios of
___________ from
reciprocal crosses
• Autosomal genes show
____ ratios from
reciprocal crosses |
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Definition
| dominant, progeny eye colors, same |
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Term
Presence of _______ determines
maleness (sry gene) in humans; female
is _______ |
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Definition
| y-chromosome, default sex |
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Term
| Genes on sex chromosomes are ____ involved in sex functions |
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Definition
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Term
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Definition
– low in number of genes
– heterochromatic (highly condensed) |
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Term
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Definition
– DNA sequences that are substantially similar on X
and Y chromos |
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Term
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Definition
| – DNA sequences/genes that contain no counterpart on other sex chromosome |
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Term
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Definition
They pair and segregate during meiosis,
even though they are very different. |
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Term
| X chromosome structure, top to bottom. |
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Definition
| Psuedoautosomal region 1, centromere, psuedoautosomal region 2 |
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Term
| Y chromosome structure, top to bottom |
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Definition
| Psuedoautosomal area 1, Maleness gene SRY, centromere, psuedoautosomal area 2 |
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Term
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Definition
| – Genes in the differential region of X |
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Term
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Definition
| – Genes in the differential region of Y |
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Term
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Definition
– In Males, the genes found in the differential region of X
– Have no counterpart on Y
– Are neither heterozygous nor homozygous
– Means “half zygous |
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Term
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Definition
– Either X or Y linked genes
– Not autosomal linkage |
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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.
Examples- colorblindness, hemophilia |
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Term
X Linked Recessive Disorders
Pedigree Feature |
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Definition
More males than females show
the phenotype
• NONE of the progeny of
affected male show the
phenotype
– (unless mother is carrier or
affected)
• ALL of daughters of affected
male are carriers
(heterozygotes)
• Sons of affected male NEVER
show the phenotype EVER (no
matter the mother’s deal)
• Daughter will show phenotype
ONLY IF both her mother and
her father have the allele |
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Term
| X-linked dominant traits: |
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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 ricket |
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