Question

In vultures, an individual with shortened wings is called a lowflyer. When lowflyers are mated to normals, they produce 1/2 lowflyer and 1/2 normal progeny. When lowflyers are mated to lowflyers, they produce a 2 lowflyer: 1 normal ratio. Which of the following can explain these results?

Answer 1

The observed breeding patterns in vultures suggest Mendelian inheritance with incomplete dominance where 'lowflyer' is heterozygous and the homozygous condition is lethal, which is analyzed using a Punnett square to predict phenotypic ratios.

Step-by-step explanation:

The breeding results given in the question suggest a Mendelian inheritance pattern with incomplete dominance. When a 'lowflyer' is crossed with a 'normal', we observe a 1:1 ratio which indicates that the 'lowflyer' trait is due to a heterozygous condition, with one allele being dominant for normal wing length and the other allele being incompletely dominant for shortened wings. We can represent the normal allele as 'N' and the lowflyer allele as 'L'. With the cross of two lowflyers, resulting in a 2 lowflyer : 1 normal ratio, it indicates that when two heterozygous individuals (L/N) are crossed, the resulting genotypic ratio of 1 LL: 2 LN: 1 NN translates into a phenotypic ratio where the 'LL' genotype is lethal or not viable, hence we only observe the surviving 2 LN (lowflyer) and 1 NN (normal) offspring.

A Punnett square for the cross of LN x LN would show:

• L N
• L LL LN
• N LN NN

With LL not surviving, we see the 2:1 ratio. This analysis demonstrates the power of the Punnett square in predicting inheritance patterns and understanding genetics in organisms such as vultures or fruit flies (Drosophila melanogaster).