Question

Скрестили двух кроликов: самка – окраска рыжая, длинношёрстная, самец – окраска чёрная, короткошёрстый. Определите генотипы родителей и потомков в F 1, а также перечислите все возможные генотипы и фенотипы крольчат ( F 2) от скрещивания между собой потомков первого поколения. Рыжая окраска шерсти (А) и длинношёрстность (В) – доминантные признаки. Оба родителя гомозиготны по каждой паре аллелей. Гены не сцеплены.

Answer 1

Р1 мать ААВВ + отец аавв
F1 АаВв рыжие длиннош(анализирующее скрещивание)
Р2 мать АаВв+ отец АаВв
F2 ААВВ,АаВв,АаВВ,АаВВ рыжие длинношерст
ААвв,Аавв рыжие короткошестные
ааВв,ааВВ черные длиннош
аавв черные короткош

Answer 2

Genotype and Phenotype of the Parents and F1 Offspring

To determine the genotypes of the parents and F1 offspring, we need to analyze the given information about their phenotypes.

The female rabbit has a red (ryzhaya) coat color and is long-haired (dlinnoshyorstnaya). Let's assign the dominant allele for red coat color as "A" and the dominant allele for long hair as "B". Therefore, the female rabbit's genotype can be represented as AABB.

The male rabbit, on the other hand, has a black (chornaya) coat color and is short-haired (korotkoshyorstny). Using the same allele notation, we can represent the male rabbit's genotype as aabb.

Since both parents are homozygous for each pair of alleles, we can conclude that the female rabbit is homozygous dominant (AABB) and the male rabbit is homozygous recessive (aabb).

When these two rabbits are crossed, their offspring in the F1 generation will inherit one allele from each parent. Therefore, all the F1 offspring will have the genotype AaBb.

Genotypes and Phenotypes of the F2 Offspring

To determine the possible genotypes and phenotypes of the F2 offspring, we need to consider the possible combinations of alleles from the F1 generation.

In the F1 generation, each offspring will receive one allele for coat color (A or a) and one allele for hair length (B or b) from each parent. Therefore, there are four possible combinations of alleles for each trait: AB, Ab, aB, and ab.

To determine the genotypes and phenotypes of the F2 offspring, we need to consider all possible combinations of these alleles. By multiplying the possibilities for each trait, we can determine the total number of genotypes and phenotypes.

For coat color: - AA (red) crossed with AA (red) can produce offspring with the genotype AA (red). - AA (red) crossed with Aa (red) can produce offspring with the genotypes AA (red) and Aa (red). - Aa (red) crossed with Aa (red) can produce offspring with the genotypes AA (red), Aa (red), and aa (black).

For hair length: - BB (long-haired) crossed with BB (long-haired) can produce offspring with the genotype BB (long-haired). - BB (long-haired) crossed with Bb (long-haired) can produce offspring with the genotypes BB (long-haired) and Bb (long-haired). - Bb (long-haired) crossed with Bb (long-haired) can produce offspring with the genotypes BB (long-haired), Bb (long-haired), and bb (short-haired).

By combining the possibilities for coat color and hair length, we can determine all the possible genotypes and phenotypes of the F2 offspring:

Genotypes: - AA BB (red, long-haired) - AA Bb (red, long-haired) - Aa BB (red, long-haired) - Aa Bb (red, long-haired) - Aa bb (red, short-haired) - aa BB (black, long-haired) - aa Bb (black, long-haired) - aa bb (black, short-haired)

Phenotypes: - Red, long-haired - Red, long-haired - Red, long-haired - Red, long-haired - Red, short-haired - Black, long-haired - Black, long-haired - Black, short-haired

Therefore, the F2 offspring can have eight different genotypes and three different phenotypes.