A student caught a fish in a lake that was an unusual green color. She decided to investigate whether this green phenotype had a genetic basis. She obtained fish of the same species that were pure-breeding for the wildtype silver phenotype and crossed them with her green fish. The F progeny were as follows: 1 silver fish : 1 yellow fish.
'n Student het 'n vis in 'n meer gevang wat 'n ongewone groen kleur was. Sy besluit om ondersoek in te stel om te bepaal of hierdie groen fenotipe 'n genetiese basis het. Sy bekom visse van dieselfde spesie wat suiwer telend is vir die wildetipe silwer fenotipe en kruis hulle met haar groen vis. Die F nageslag was soos volg: 1 silwer vis : 1 geel vis.
a. Can a single gene with two alleles produce this result? (Answer yes or no only)
Kan 'n enkel geen met twee allele hierdie resultaat lewer? (Antwoord slegs ja of nee)
b. To follow up on the first cross, the student allowed the yellow fish from the F generation to cross with each other. The progeny of this cross were as follows: 6 yellow : 3 silver : 2 green : 1 brown. How many genes appear to be involved in determining these phenotypes?
Om op te volg op die eerste kruising het die student die geel visse vanaf die F generasie toegelaat om met mekaar te kruis. Die nageslag van hierdie kruising is soos volg: 6 geel : 3 silwer : 2 groen : 1 bruin. Hoeveel gene is blykbaar betrokke by die bepaling van hierdie fenotipes?
C. The student attempted to generate a pure-breeding green line of fish by inbreeding. She found that this was impossible. Every time she crossed two green fish, she obtained progeny in a 2 green : 1 brown ratio. What does this ratio suggest?
Die student probeer om 'n suiwer telende groen lyn visse deur inteling te skep. Sy het dit onmoontlik gevind. Elke keer wat sy twee groen visse gekruis het, het sy nageslag gekry in 'n 2 groen : 1 bruin verhouding. Waarop dui hierdie verhouding?
d. Based on all the information above, provide one possible genotype for each phenotype of the progeny of the cross in (b). Use A for the allele that modifies the expected ratio.
Gebaseer op al die inligting hierbo, verskaf een moontlike genotipe vir elke fenotipe van die nageslag van die kruising in (b). Gebruik A vir die alleel wat die verwagte verhouding verander.
Genotype: Genotipe:
Phenotype: Fenotipe:
6 yellow geel
3 silver silwer
2 green groen
1 brown bruin
