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78 Cards in this Set
- Front
- Back
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The Blending Theory of Inheritance
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(Mid 1800s)
Offspring are intermediate compared to parents. Problem with this is that people would eventually become uniform. or inbred. |
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Gregor Mendel
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"The Father of Genetics"
Demonstrated that inherited characteristics are carried by discrete units in each generation. Known as GENES |
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Self-Pollinating
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AKA True Breeding.
True Breeders possess both sexes. If fertilized by same plant then offspring will be identical |
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Simultaneous Hermaphrodite
Anther Stigma |
Produces both egg and seed.
Anther is the flowers female part Stigma is the male part |
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Trait
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Characteristic of an organism such as height, weight, eye color, behavorial, etc.
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Phenotype
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Physical, Outward appearance of trait.
Expressed as observation such as Tall, Short, Blue, Red...etc. |
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Discontinuous Trait
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No gradient, expressed as one trait or another.
Tall or Short given a T or t. But not intermediate given the same genes. |
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Genotype
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Alleles an individual has for a trait (BB,Bb,bb). Most genes are more complicated than this.
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Allele
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Form of a trait or a different way that a gene can be expressed.
Ex: Eye Color (gene) - Green Eyes (allele), Brown eyes (allele) |
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Chromosomes
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Packages of Genes
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Dominant Allele
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Has the ability to mask expression of recessive allele and is represented by an uppercase letter
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Recessive Allele
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Only expressed if not coupled with a dominant allele. Represented by a lower case letter.
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Homozygous Dominant
Homozygous Recessive Heterozygous |
Dominant gene coupled with another dominant gene.
Recessive gene coupled with another recessive gene. A Dominant gene coupled with a recessive gene. |
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Monohybrid Cross
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Cross involving one trait. Should be identical in every other trait
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Dihybrid Cross
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Cross involving two traits
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P (parental) generation
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Original parents in first class
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F1 (Filial generation 1)
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Offspring produced by crossing original parents - this shows which color is dominant
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F2 Generation
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Offspring resulting from an F1 x F1 cross.
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Reciprocal Cross
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Repeating a cross, but changing the sex of the parent possessing a specific allele
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Reginal Punnett and his squares
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Famous Poultry Geneticist...?
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Mendels Law of Segregation
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Each organism contains two genes for each trait. These genes separate during meiosis and produce haploid gametes (with one allele from the pair). When fertilization occurs, the new organism will have two factors for each trait - one from each parent
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Mendels Law of Independent Assortment
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Got this from a dihybrid cross. The first was from a monohybrid cross. Members of one pair of genes segregate into gametes independently from another pair of genes.
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Test Cross
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A specific Mono or Dihybrid cross. Used to find out of a phenotypically dominant speciman is homo or hetero.
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P (parental) generation
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Original parents in first class
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Incomplete Dominance
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Heterozygote instead of Rr Ending up as Red, it makes use of both alleles and makes it Pink (red and white)
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Codominance
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When 2 dominant genes are expressed. example is AB blood
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F1 (Filial generation 1)
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Offspring produced by crossing original parents - this shows which color is dominant
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F2 Generation
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Offspring resulting from an F1 x F1 cross.
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Reciprocal Cross
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Repeating a cross, but changing the sex of the parent possessing a specific allele
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Reginal Punnett and his squares
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Famous Poultry Geneticist...?
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Incomplete Dominance
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Heterozygote instead of Rr Ending up as Red, it makes use of both alleles and makes it Pink (red and white)
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Codominance
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When 2 dominant genes are expressed. example is AB blood
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Gamete?
Contain how many Chromosomes? |
Egg or Sperm.
Each Contain 2 Chromosomes. |
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Zygote?
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Fused Egg and Sperm that each (gamete-containing 2 chromosomes) contain half the complement of chromosomes.
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Meiosis?
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Reduction Division.
Produces cells with half the normal number of chromosomes. |
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Diploid Cells.
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Cells with 2 sets of chromosomes.
(Fertilized Egg) |
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Haploid Cells
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Only one set of chromosomes are found. (gametes)
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Sexual Reproduction is the alternation of _____ and _____
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Meiosis & Fertilization
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Germ-line Cells
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Cell in most animals that are set aside early in development to eventually become haploid cells for reproduction.
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Prophase I of Meiosis
(Page 209) |
DNA coils tightly,
Chromosomes become visible as matrix of threads (light microscope). Each thread = 2 sisters Chromatids joined at centromeres. Homologous Chromosomes (2 pairs of sisters) come close. Create synapse Exchange genetic segments by crossing over. Separate. Nuclear Envelope Disappears. Microtubules become the K spindles. |
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SYNAPTONEMAL COMPLEX (aka tetrad or bivalent)
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Lattice of proteins between two homologous chromosomes that are paired. (4 Chromotids)
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Crossing Over (Prophase 1) (aka recombination)
(Page 210) |
Homologous paired chromosomes exchange genetic information
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Chiasmata (Prophase 1)
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The site of crossing over.
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Interphase for Meiosis (stages)
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Similar to Mitosis, G1 (growth), S (DNA Synthesis), and G2 (short phase, rapid growth) phases.
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Metaphase I of Meiosis
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Chiasmata move down paired chromosomes.
They become Terminal Chiasmata. K. Spindles attach to homologues (Not SISTERS). Paired homologues are pulled to to equator (Metaphase Plate). |
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Terminal Chiasmata
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Chiasmata that have moved down a pair of chromosomes.
Hold homologous chroms. together during Metaphase I so that they can be aligned at the equator. |
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Anaphase I of Meiosis
(Page 211) |
Spindle Fibers shorten.
Chiasmata is broken, pulling chromosomes to poles. Each pole will have complete haploid set of chrom. |
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Telophase I of Meiosis
(Page 211) |
Chroms. have segregated into 2 clusters, one at each pole.
Nuclear Membrane Reforms around each daughter nucleus. |
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Break Time
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Have a beer.
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Prophase II of Meiosis
(Page 211) |
Clusters of chromosomes are at the two poles.
Each Nuclear Envelope breaks down, new spindle forms. |
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Metaphase II
(Page 211) |
Same as regular Metaphase (of Mitosis)
Spindle Fibers bind to kinetochores of each sister chromatid, allowing each chromosome to migrate to the metaphase plate. |
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Anapahse II
(Page 211) |
Spindle Fibers contract, breaking the centromeres.
Sister chromatids are pulled to different poles individually. (same as regular mitosis) |
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Telophase II
(Page 211) |
Nuclear Envelope reforms around the 4 sets of daughter chromosomes.
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Polygenic Inheritance
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Combined effects of many genes control trait expression.
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Pleiotropy
(Hint) Ex1: Collagen Ex2: Deaf, Blue-eyed, white cats |
A single gene affects more than one characteristic. The same gene product (protein) may be involved in many metabolic pathways.
Ex 1: Collagen Ex2: Deaf, Blue-eyed, white cats - if the cat gets 2 recessive alleles from specific gene, it cause these three effects. |
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Environmental Phenotype
(_____ x _____) Ex#1 Buttercup Leaves Ex#2 Human Skin color |
Genotype X Environment
Ex#1 Buttercup leaves differ in structure and function depending whether they are in water or land. Ex#2 Human Skin Color |
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Expressivity (Heredibility)
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The degree to which a particular genotype is expressed as phenotype.
Ex (Wiki): the "blue" gene might have an expressivity of 25% for individuals that express the "blue" gene and appear light blue, and 75% for individuals that express the "blue" gene and appear dark blue. |
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Linkage Group
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Genes stay together because they are on the same chromosome.
(Contradicts Mendels Law of Independent Assortment: Genes for multiple traits are independent) |
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How are Chroms. Listed?
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In order of decreasing length.
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When does the 9:3:3:1 ratio occur?
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Dihybrid Cross; F2 Generation; Parents must be heterozygous for both traits; May only be Complete Dominance.
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What determines how many cross overs will occur?
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Length of Chromosomes.
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What did Thomas Hunt Morgan study, and why?
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Fruit Flys. Have only 3 pairs of chromosomes. Large Chroms.
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Autosome?
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Chrom. that is not a sex chrom. Equal # in males/females.
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Sex Chromosomes
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The strucutre of one pair of chromosomes that differ between sexes of the same species.
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Sex Linkage
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Genes for trait are located on sex chroms.
Most traits (in humans) are carried in the X. (Linkage - Genes are on the same chromosomes) |
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Homogametic
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Pair of sex chroms. that are the same.
(Ex: XX in H. Female.) |
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Heterogametic
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Pair of sex chroms. that are different
(Ex: XY in H. Male) |
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Hemizygous
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The heterogametic sex genotype for a sex linked trait.
(When only 1 Gene for specific trait is available, such as in H. Males XY, most are on X) Neither Homo or Heterozygous |
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Lyon Hypothesis
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One or the other X chroms. in a female is inactive.
Proposed by Mary Lyon. Used Cats. |
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Barr Body
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Dark spot that is seen on the outer edge of nucleus in females.
This is the inactive X which never completely decondensed. |
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What causes Mutations?
(Name, and examples) |
Mutagens - UV light, pesticides, environment.
May include gene or entire chrom. |
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Does a mutation affect organism survival?
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Can be harmful, helpful, or make no difference.
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Aneuploidy
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One or a few chromosomes are missing or additional chromosomes are present.
(Many Birth defects) |
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Polyploidy
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Changes in entire sets of chroms.
(some wheat species are hexaploids, 6N) |
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Deletion
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Segment(s) are missing
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Duplication
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Segment(s) appear more than once.
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Translocation
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Segment(s) are transferred to a non-homologous chromosome
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Inversion
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Segment(s) are broken off and reattaches with a 180 degree turn.
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