University:
University of New Mexico
Course:
BIOL 412 | Developmental Biology
Academic year:

2020
Views:

190

Pages:

4
Author:

Dania Lynch

Cell Division and Heredity (health) Worksheet Monohybrid cross 1 Using the appropriate notation, and the Punnett square below, identify the phenotype and genotype ratios of a cross between two parents that are heterozygous for handedness. Female R r R Rr RR Male r Rr rr Phenotype ratio = 3:1 right handed to left handed Genotype ratio = 1 (RR):2(Rr):1(rr) = 1:2:1 Monohybrid cross 2 Using the appropriate notation, and the Punnett square below, identify the phenotype and genotype ratios of a cross between a female with blood type AB (I AIB) and a male whose genotype is IBIO Female IA IB IB IB IB IBIA Male IO IA IO IOIB Phenotype ratio = 1 IA 2 IB 1 IO – 1:2:1 Genotype ratio = 1 (IA):1(IBIB):1(IAIO):1(IOIB) – 1:1:1:1 1 Sex linkage Using the appropriate notation, and the Punnett square below, identify the phenotype and genotype ratios of a cross between a colour blind male and a carrier female. Female (Carrier) XB Xb XB Xb XB XB XB Normal Colour vision female Male XB Xb red-green colour blindness carrier female (Normal Vision) XB Y Y XB Y X bY Normal colour vision male Red-green colour-blind male Phenotype ratio = 1 XbXb: 1XBXb: 1XbY: 1:XbY = 1:1:1:1 Genotype ratio = 1 XBXB 1 XBXb 1 XBY 1XbY =1:1:1:1 Dihybrid In alpacas, white hair (H) is dominant over brown hair (h), and long hair (L) is dominant over short hair (l). If a pure bred alpaca with long white hair (HHLL) was crossed with an alpaca with short brown hair (hhll) what would be the phenotype and genotype ratios in the first generation? Please use the Punnett square below to show your workings. f1 Generation Female HH hh Male LL LLhh HHhh ll HHll LLll Phenotype ratio = 1:1:1:1 Genotype ratio = 1:1:1:1 2 f2 generation If two of the f1 generation were then crossed, what would be the phenotype and genotype of the offspring. Female HL hL Hl hh HL HLHL HLLh HHLl HHhh hL HLLh LLhh HLhl Lhhh Hl HHLl HLhl HHll Hhhl Hl HLhl LHHl Hllh hhhl Male Phenotype ratios = 9:3:3:1 Genotype ratios = 1:2:2:1:4:1:2:2:1 3 Pedigree analysis The below pedigree represents the inheritance of haemophilia within a family. Haemophilia is a sex linked recessive condition. Use XH to represent the “normal” version of the gene and Xh to represent the “faulty” gene to analyse this chart. Then answer the questions below. Remember, there is no allele carried on the Y chromosome. 1. How many generations are shown in this chart? 3 2. How many children did couple 1 and 2 have? 4 3. What is the genotype of individual 2? Xh 4. What is the genotype of individual 4? XH 5. What is the genotype of individual 10? XH 6. What is the genotype of individual 12? Hh 7. If couple 7 and 8 had another child what is the probability that the offspring will be affected? 100% 4/4 8. If individual 9 married an affected male what would be the probability of a male child being affected with haemophilia? 50% 1/2 4