Flashcards
Lecture 10 (pt. 2) Mendel and the Gene idea
Cards in this deck (41)
- 1Gregor Mendel (1840s)– Austrian monk
– Background as a farmer
– Statistician (strong background in mathematics) - counted the different types of offspring
– Worked with pea plants Pisum sativum
– He was a plant breeder and a mathematician - 2Pea Plants are great genetic model organism– Inexpensive
– Short lifetime
– Many observable traits
– Lots of progeny
– Self-fertilizing
– Can be cross-fertilized
– Pea plant offspring can be used to describe the heredity patterns of traits (how information is passed from parent to offspring) - 3Genes– Units of information about specific traits, passed from parent to offspring
– Each gene has a specific location (locus) on a chromosome. - 4LocusThe specific location or position of a gene, DNA sequence, on a chromosome
- 5Chromosome– DNA and its associated proteins - involved in the hereditary information of cells
- 6Alleles– Different molecular forms of the same gene
– Example: The gene for eye color has 2 alleles. The allele can either contain the gene for blue eye color or the gene for brown eye color. - 7Diploid- (2n) = pairs of genes on pairs of homologous chromosomes (the chromosomes of the same chromosome type - have the same size and shape)
-A cell containing two complete sets of chromosomes, one from each parent. - 8Haploid– (n) = has half the number of chromosomes (gametes)
- 9True-Breeding Lineage– When offspring of genetic crosses (breeding) that inherit two identical alleles for the same exact trait. All offspring will have the same trait as their parents.
– Example: All offspring of a true breeding purple flowered pea plant will have purple flowers. - 10True breedingAlso called a purebred, is an organism that always passes down certain phenotypic traits to its offspring.
- 11Hybrid offspring– When offspring of a genetic cross inherit a pair of non-identical alleles for a trait
– Example: Two purple flowered plants produce a white flowering offspring
– Aa, aA - 12Homozygous dominant–Both alleles for the same trait are dominant
-AA - 13Homozygous recessive– Both alleles for the same trait are recessive
-Aa - 14Genotype–The particular genes an organism carries. Show you the pattern of alleles
AA (purple flower)
Aa (purple flower)
aa (white flower) - 15PhenotypeAn individual’s observable physical traits (purple flower, white flower)
- 16Homozygous-When both alleles of the pair for a certain trait are identical.
-2 of the same alleles - 17Heterozygous– When the two alleles of a pair for a certain trait are different
- 18Terms used for tracking the inheritance of traits through generations of offspring-P= Parental generation
- F1= First generation of offspring (first filial)
-F2= Second generation of offspring (second filial) - 19Monohybrid–Only one trait is followed through a series of genetic crosses.
- 20Dihybrid-Two traits are followed through a series of genetic crosses
- 21Mendel's theories-Theory of segregation
-Theory of independent assortment - 22Theory of segregationDuring meiosis, the two genes of each pair segregates from each other and end up in different gametes. (alleles separate into different gametes)
• Monohybrid cross
• Gene segregation - 23Theory of independent assortmentBy the end of meiosis, the genes on pairs of homologous chromosomes have sorted independently (into gametes). Deals with different traits
- 24ProbabilityThe likelihood that a particular event will happen (flipping a coin)
- 25Probability and Punnett squares–A possibility of outcomes and crosses
–Test crosses - 26–What are five factors that can influence patterns of heredity?-Incomplete Dominance
-Codominance
-Multiple Alleles
-Continuous Variations
-Environmental influences - 27Incomplete Dominance-An individual displays a trait that is intermediate between the 2 parents (snapdragons).
-If you have one allele of each you’re going to have a blend of dominant and recessive.
(EX. 1 recessive White and 1 dominant red blended heterozygous pink) - 28Codominance-Two alleles are expressed at the same time (roan coat).
-Heterozygous dominant is going to have both alleles showing both colors
(ex. Red D and white R the flower will have some of each). - 29Multiple Alleles-Genes that have traits with more than 2 alleles-blood type has 3 alleles (A,B,O) that determine blood type.
-More than just A and a.
-When there is a third option of an allele for one genotype. More than one gene interacting to form a trait. - 30Continuous Variation-Traits for which you see a variety of phenotypes on a continuum from one extreme to another (height, weight).
-Many genes and 1 trait. - 31Environmental Influences-An individual’s phenotype often depends on conditions in the environment.
-Example: Many animals such as the arctic fox develop white fur during the cold winter and dark fur in the summer. - 32How blood types are inherited and expressed:–Type A (AA)
–Type AB (AB)
–Type B (B i) (BB)
–Type O (I I ) - 33PleiotropyEffects on two or more traits
Ex. Sickle cell anemia - 34Epistasis -Interactions among products of two or more gene pairs
-Two alleles of one gene may mask the expression of another gene’s alleles- so some expected phenotypes may not appear. - 35Hair color in mammals-Variation in melanin products (Ee, EE, ee) ››allele “E” allows full deposition of melanin
-Albinism (total absence of melanin product) - 36Comb shape in poultry-Interaction between two gene pairs produces a phenotype that neither pair can produce alone
- 37Hair color in Labrador Retrievers (epistasis)-Black (Dominant pigment, dominant 2nd pair)
-Yellow (recessive pigment and dominant or recessive 2nd pair)
-Brown (dominant pigment and recessive for 2nd pair) - 38Continuous variation-Eye color
-Different amounts of melanin
-Different enzymes affect the production - 39Continuous variation (normal distribution)-Height
-The greater number of genes and the environmental factors, the more continuous will be the expected distribution of the trait. - 40-Examples of environmental effects on phenotypes– Himalayan rabbit
– Siamese cat
– Heat-sensitive version of enzyme needed for melanin production
Warm= white fur
Cold= dark fur - 41Hydrangea-Plants that have the same alleles and have flowers colors raging from pink to blue depending on the acidity of the soil.
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- Flashcards on Lecture 10 (pt. 2) Mendel and the Gene idea , created by Sydney Franko on 11/04/2016.
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