Download presentation
Presentation is loading. Please wait.
Published bySharon Berry Modified over 8 years ago
1
1 Mendelian Genetics
2
2 Gregor Mendel The Father of Genetics
3
3 Gene A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA (or RNA in some viruses)
4
4 Alleles Alleles are alternate forms of a gene. Examples: tall and short for plant height or purple or white for flower color. Every trait has at least two alleles- one from each parent. The location of an allele on a chromosome is known as its locus (loci = plural form).
5
5 Genotype The letters that represent (symbolize) the trait being investigated. The genetic make- up of an organism. Examples: Bb, BB, bb
6
6 Phenotype The actual representation of the genes. The Physical appearance or traits in an organism resulting from its genetic makeup (what you see). Examples: tall, purple flower or white flower, blond hair, freckles, etc.
7
7 Dominant The allele that is fully expressed in an organism (observed). Represented by capital letters. Tall = T
8
8 Recessive The allele that is masked by the dominant allele. Represented by lower case letters. Short = t
9
9 Homozygous When both alleles (letters) are the same. BB = Homozygous Dominant bb = Homozygous recessive
10
10 Heterozygous When the alleles (letters) are different. One upper case letter and one that is lower case. Bb = Heterozygous
11
11 Example Problem Round = R wrinkled = r If a plant has round seeds, do we know what its genotype is? It could be RR or Rr If a plant has wrinkled seeds, do we know what its genotype is? Yes, it is rr.
12
12 Punnett Square A method for finding predicted outcomes and probabilities for offspring from any cross. A chart for predicting the traits of offspring.
13
Some more terms: P-generation is the parental generation. The p-generation produce the F1 generation. The F1 generation crossed with itself produces the F2 generation. 13
14
Example Problem 14
15
In foxes, red coat color is determined by the dominant gene R; silver-black coat is determined by the recessive gene r. A homozygous (pure) red male is crossed with a silver-black female. (The P generation). 15 1.What is the genotype of the female?
16
What are the genotype percentages of their offspring? First…make a Punnett square for showing your work 16
17
17 Example Problem r r RR Rr
18
18 Assignment Section 32-3
19
19 Assignment 33-4 & 33-5
20
20 #1 b b Bb Bb bbBb bb B = Brown b = blue 1 point
21
21 #1 1/2 or 50% chance of blue-eyed. 1/2 or 50% chance of Brown-eyed. 1 point
22
22 #2 t t Tt Tt ttTt tt T = Tall t = short 1 point
23
23 #2 What fraction of offspring would be tall? 1/2 or 50% would be Tall. 1 point
24
24 #3 w W Ww Ww WW ww W = White w = black 1 point
25
25 #3a What fraction of the offspring will be white? 3/4 or 75% will be white. 1 point
26
26 #3b What fraction of the offspring will be black? 1/4 or 25% will be black. 1 point
27
27 #3c What fraction of each genotype will you get? 1/4 or 25% will be WW 1/2 or 50% will be Ww 1/4 or 25% will be ww. 1 point
28
28 #3d What fraction of each phenotype will you get? 3/4 or 75% will be White. 1/4 or 25% will be black. 1 point
29
29 #4 W W RR RW RR = Red WW = White RW = Roan 1 point
30
30 #4 Give the fraction of each color of offspring? 1/1 or 100% will be Roan - RW. 1 point
31
31 #5 W W RW RW WWRW WW RR = Red WW = White RW = Roan 1 point
32
32 #5 Give the fraction of each color of offspring? 1/2 or 50% will be Roan - RW. 1/2 or 50% will be White - WW. 1 point
33
33 #1a g G Gg Gg GG gg G = Green g = red 1 point
34
34 #1a Give the fraction of each genotype of offspring? 1/4 or 25% will be GG. 1/2 or 50% will be Gg. 1/4 or 25% will be gg. 1 point
35
35 #1b g g Gg Gg ggGg gg G = Green g = red 1 point
36
36 #1b Give the fraction of each genotype of offspring? 1/2 or 50% will be Gg. 1/2 or 50% will be gg. 1 point
37
37 #2a What is the fraction of each phenotype? 3/4 or 75% will be Green. 1/4 or 25% will be red. 1 point
38
38 #2b What is the fraction of each phenotype. 1/2 or 50% will be Green 1/2 or 50% will be red. 1 point
39
39 # 3 The mother had to be heterozygous or Bb since the couple had a blue eyed child. b B bb bb Bb bb 1 point
40
40 # 4 There would be a 50% chance that the 2nd child from the couple would have a brown eyes. 1 point
41
41 # 5 Spotted = S white = s Mother = ss since she is white. Father’s Genotype would be Ss. Father’s Phenotype would be Spotted The couple had two spotted and two white kittens. 2 points
42
42 # 6 Man has blue eyes - bb. G-Ma has blue eyes - bb. Woman has brown eyes - Bb. 50% of children would be Bb. (Brown) 50% of children would be bb. (Blue) 5 points
43
43 Please put a score on top of their paper. Put the number correct out of 28
44
44 Punnett Squares Why are punnett squares useful? We can use a punnett square to predict the probable genotypes and phenotypes for offspring from a genetic cross. Genotype = What is inside the genes, the make-up. Phenotype = The outward expression of the genes.
Similar presentations
© 2024 SlidePlayer.com Inc.
All rights reserved.