Question

Пожалуйста помогите 1 . Гипертрихоз передается через Y- хромосому, а полидактилия – доминантным аутосомным геном. В семье, где отец имел гипертрихоз, а мать полидактилию, родилась нормальная в отношении обоих признаков дочь. Какова вероятность того, что следующий ребенок в семье будет без этих аномалий? Какова вероятность того, что внуки родителей (от дочери) будут иметь тот или иной из этих признаков, при условии, что она выходит замуж за здорового мужчину? 2 . У канареек сцепленный с полом ген В определяет зеленую окраску оперения, b - коричневую. Коричневого самца скрещивают с зеленой самкой. Какое соотношение фенотипов и генотипов ожидается в F1 и F2 этого скрещивания? 3. У кошек желтая окраска шерсти определяется доминантным геном В, черная - b. Гетерозигота Вb имеет черепаховую окраску шерсти. Ген В сцеплен с полом. Какие могут быть котята, если кот черный, а кошка желтая; если кот черный, а кошка черепаховая? Может ли кот иметь черепаховую окраску?

Answer 1

Ответ:

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Объяснение:

Answer 2

Hypertrichosis and Polydactyly Inheritance

Hypertrichosis is transmitted through the Y chromosome, while polydactyly is determined by a dominant autosomal gene. In a family where the father has hypertrichosis and the mother has polydactyly, a daughter is born who is normal for both traits. The question asks about the probability of the next child in the family being without these anomalies and the probability of the grandchildren (from the daughter) having one or the other of these traits when she marries a healthy man.

To answer these questions, we need to consider the inheritance patterns of hypertrichosis and polydactyly.

Inheritance of Hypertrichosis

Hypertrichosis is transmitted through the Y chromosome. Since the father has hypertrichosis, he must have inherited the Y chromosome with the hypertrichosis gene from his father. As a result, all his sons will also have hypertrichosis, while his daughters will not inherit the Y chromosome and will not have hypertrichosis.

Inheritance of Polydactyly

Polydactyly is determined by a dominant autosomal gene. Since the mother has polydactyly, she must have inherited the polydactyly gene from one of her parents. The fact that she is affected by polydactyly means that she is heterozygous for the gene, meaning she has one copy of the polydactyly gene and one copy of the normal gene. If she passes on the normal gene to her child, the child will not have polydactyly.

Probability of the Next Child Being Without Anomalies

Since the daughter is normal for both hypertrichosis and polydactyly, we can conclude that she inherited the normal gene for both traits from both her father and mother. Therefore, the probability of the next child in the family being without these anomalies is 100%.

Probability of Grandchildren Having One or the Other Trait

If the daughter marries a healthy man, we can assume that he does not have the hypertrichosis or polydactyly genes. Since the daughter does not have the hypertrichosis gene and has a 50% chance of passing on the polydactyly gene, the probability of her children having hypertrichosis is 0%. Similarly, the probability of her children having polydactyly is 50%.

Phenotypic and Genotypic Ratios in F1 and F2 Crosses

In the case of canaries, the gene B determines green feather color, while the gene b determines brown feather color. When a brown male is crossed with a green female, the expected phenotypic ratio in the F1 generation is 100% green. This is because the gene for green feathers is dominant over the gene for brown feathers.

In the F2 generation, if the F1 birds are crossed with each other, the expected phenotypic ratio is 3 green:1 brown. This is because the F1 birds are heterozygous (Bb) and can produce both green and brown offspring.

The expected genotypic ratio in the F2 generation is 1 BB:2 Bb:1 bb. This is because the F1 birds can produce offspring with three different genotypes: homozygous dominant (BB), heterozygous (Bb), and homozygous recessive (bb).

Possible Offspring in Cats

In cats, yellow fur color is determined by the dominant gene B, while black fur color is determined by the recessive gene b. A heterozygous cat (Bb) has a tortoiseshell or calico fur color, which is a mix of yellow and black fur.

If a black male cat mates with a yellow female cat, the possible offspring can be: - If the male cat is homozygous for the black fur color gene (bb) and the female cat is homozygous for the yellow fur color gene (BB), all the offspring will be heterozygous (Bb) and have tortoiseshell or calico fur color. - If the male cat is homozygous for the black fur color gene (bb) and the female cat is heterozygous (Bb), the possible offspring can be black (bb) or tortoiseshell/calico (Bb). - If the male cat is heterozygous (Bb) and the female cat is homozygous for the yellow fur color gene (BB), the possible offspring can be yellow (BB) or tortoiseshell/calico (Bb).

A male cat cannot have tortoiseshell or calico fur color because it can only inherit one X chromosome from its mother. Tortoiseshell or calico fur color requires two X chromosomes.

I hope this information helps! Let me know if you have any further questions.