Question

The LMand LNalleles at the MN blood-group locus exhibit codominance. Give the expected genotypes and phenotypes and their ratios in progeny resulting from the following crosses.a.LMLM x LMLNb.LNLN x LNLNc.LMLN x LMLNd.LMLN x LNLNe.LMLM x LNLN

Answer 1

Answer:

Please find the expected genotypes and phenotypes of the progenies of each cross below.

Explanation:

In the MN blood-group locus of the gene, alleles LM and LN exhibit codominance i.e one allele is not dominant or recessive to the other, hence, they are both expressed when they occur in a heterozygous state (MN).

Considering the following crosses (find the punnet square attached);

a)LMLM x LMLN - The progeny are LMLM and LMLN in the genotypic ratio 1:1. Phenotypic ratio is Blood type M (1) : blood type MN (1)

b) LNLN x LNLN - The progeny are all LNLN offsprings with a phenotypic and genotypic ratio 4:0. All offsprings will have a blood type N (4)

c) LMLN x LMLN - The progenies are LMLM, LMLN and LNLN in the genotypic ratio 1:2:1 respectively. The phenotypic ratio is Blood type M (1) : L

Blood type MN (2) : Blood type N (1)

d) LMLN x LNLN - The progeny are LMLN and LNLN with genotypic ratio 1:1 and phenotypic ratio blood type MN (1) : blood type N (1)

e) LMLM x LNLN - The progeny are all LMLN offsprings with penotypic ratio blood type MN (4)