Question

to better studies of the genetics of pelvic spines, scientists collected data from two generations of stickleback fish, bred from a parental generation with one stickleback fish with spines and one fish without spines. their data are shown below. (table: parental generation: with spines - 1, without spines - 1, total fish - 2, ratio - ----; f1 generation: with spines - 16, without spines - 0, total fish - 16, ratio - ----; f2 generation: with spines - 30, without spines - 10, total fish - 40, ratio - 3:1) complete the sentences about the crosses the scientists completed. all of the fish in the f1 generation are choose the cross between two f1 fish was a choose cross. (options for first choose: dihybrid, monohybrid) drag and drop the claim you can make about how pelvic spines are inherited based on this data as well as one piece of evidence that supports your claim.

Explanation:

1. For the F1 generation: The parental cross is between two fish differing in a single trait (presence/absence of pelvic spines). All F1 offspring show the "with spines" phenotype, meaning they are heterozygous for this single trait. A cross tracking one trait produces heterozygous offspring that are part of a monohybrid context, and the F1 individuals are monohybrids.
2. For the F1 cross: When two heterozygous individuals for a single trait are crossed, this is defined as a monohybrid cross. The F2 generation has a 3:1 phenotypic ratio, which is the classic result of a monohybrid cross.
3. For inheritance claim: The 3:1 phenotypic ratio in the F2 generation matches the expected ratio for a trait controlled by a single gene, where the "with spines" allele is dominant and the "without spines" allele is recessive. The evidence is the 30:10 (3:1) split of with spines to without spines in the F2 generation, and the fact that all F1 offspring had spines (showing the dominant trait masks the recessive one in heterozygotes).

Answer:

All of the fish in the F1 generation are monohybrid. The cross between two F1 fish was a monohybrid cross.

Claim: Pelvic spine presence is a Mendelian trait, where the allele for having pelvic spines is dominant, and the allele for no pelvic spines is recessive.
Evidence: The F2 generation shows a 3:1 ratio (30 fish with spines : 10 fish without spines) of phenotypes, which is the classic expected ratio for a single dominant-recessive gene inheritance pattern. Additionally, all F1 offspring had pelvic spines, showing the dominant trait is expressed in heterozygous individuals.