6.4 Write genotypes correctly to indicate if two genes are linked or not and if linked, the arrangement of the alleles on homologues.

6.5 Distinguish between cis and trans allele arrangements.

"The genotype of the organism producing the crossovergametes must be heterozygous at all loci underconsideration" Explain this statement ?

11). This pedigree illustrates a family in which some members have a completely penetrant disease caused by a dominant mutation. This mutation is linked at a distance of 10 map units from a SNP marker with three different alleles (1, 2 and 3). The SNP alleles found in each family member are indicated below each pedigree symbol. It is not yet evident whether the very young individuals labeled A and B will develop the disease. a. What is the probability that individual A will develop the disease? b. What is the probability that individual B will develop the disease? 1,3 2,2 1,2 3,2 O 1,2 3,2 A B

7- In peas, a tall, yellow- seeded plant is crossed with a homozygous short, green- seeded plant and yields 203 tall, green-seeded plant, 199 short, green seeded plants, 207 tall, yellow-seeded plants, and 192 short, yellow-Seeded plants. The most likely genotype of the tall, yellow-seeded plant is.. [EXPLAIN by drawing the punnett square that reflects this phenomena then select the right answer/4 a) TtYy b) TTYY c) Ttyy d) ttYY

7.18 In Drosophila, the genes st (scarlet eyes), ss (spineless bris- tles), and e (ebony body) are located on chromosome 3, with map positions as indicated: SS e 58 70 st 44 Each of these mutations is recessive to its wild-type allele (st+, dark red eyes; sst, smooth bristles; et, gray body). Phenotypically wild-type females with the genotype st ss et/st stt sste were crossed with triply recessive males. Predict the phenotypes of the progeny and the frequen- cies with which they will occur assuming (a) no interfer- ence and (b) complete interference.

What type of linkage is shown here? CH₂OH H K ОН H ОН H O Alpha (1,4) O Beta (1,2) Beta (1,6) O Alpha (1,2) O Alpha (1,6) ان O Beta (1,4) ОН CH₂OH ОН ОН H H CH2OH

6.6 Describe crossing over. Explain how it is related to recombination

2. 235O 4) Q7. Haemophiliacs possess a non-functional form of the gene responsible for the production of blood clotting factors. Shown below is the occurrence of haemophilia in one family. = male = female = male haemophiliac 7. 8. 5. 9. 3. 11 12 Usingthe following symbols: H = dominant allele h = recessive allele 1) State the genotypes of the following individuals. Individual Genotype 1. 6. 2) On the basis of the information provided, is the inheritance of haemophilia: (i) autosomal or sex-linked? (ii) dominant or recessive? 3) State the probability of individual 8 being a carrier of haemophilia. 4) Explain why only females can be carriers of haemophilia.

3.9 How many different kinds of F, gametes, F, genotypes, and F, phenotypes would be expected from the following crosses: (а) АА Х аа; (b) АА ВВ Х aa b; (c) АA ВВ СС Х аа bb cc? (d) What general formulas are suggested by these answers? ANS: F, Gametes F, Genotypes F, Phenotypes (a) 2 2 (b) 2 × 2 = 4 3 X 3 = 9 2 X 2 = 4 (c) 2 × 2 × 2 = 8 3 × 3 × 3 = 27 2 × 2 × 2 = 8 2", where n is the number of genes (d) 2" 3" 3.