Respuesta :
Explanation:
A geneticist is mapping the chromosomes of the newly captured gremlin. Stripe is heterozygous for three linked genes with alleles Ee, Hh, and Bb, that determine if gremlins are evil (E), have hair (H), and biting teeth (B). In order to determine if the 3 genes were linked, a standard testcross was done, and the 1000 offspring ...
Answer:
The correct gene order is H-e-B
Recombination frequency between genes E and B = 10%
Explanation:
In linkage parental genotype is always in greater number than recombinants, hence:
400 = eeHhBb : Parental
426 = Eehhbb : Parental
Double crossovers have the smallest number hence:
EeHhBb = 4 : Double recombinant
eehhbb = 2 : Double recombinant
Double cross over places middle allele from one sister chromatid to other one. Hence a non parental allele of the middle gene is present with parental alleles of the flanking genes.
Here recombinant type is EHB and parental type is eHB . Only gene order H-e-B would result in double cross over which would give EHB and ehb double recombinants. Hence, the correct gene order is H-e-B.
Single crossover between gene E and B would result in Heb and hEB progeny ( 48 and 46 )
Recombination frequency between E and B = [(Double recombinants + Single E and B recombinants) / Total progeny)*100]
= [ (4 + 2 + 48 + 46)/1000] * 100
= 100/1000
= 0.1 * 100 = 10%
