Question

У овец чёрная окраска шерсти полностью доминирует над белой, а длинные уши неполностью доминируют над безухостью, и гетерозиготные животные имеют короткие уши. Вышеуказанные признаки наследуются независимо. От скрещивания белых короткоухих овец с гетерозиготным чёрным длинноухим бараном получено 124 ягнёнка. Сколько получилось белых безухих ягнят? Сколько ягнят имеют такой же генотип, как у барана-отца (теоретически)?

Answer 1

124 ягнёнка всего.

возможных исходов 16

белых безухих ягнят: 3/16*124=23,25=23. 

ягнята имеющие генотип как у отца: 2/16*124=15,5=16.

ответ:23 белых безухих ягнёнка,16 имеют генотип такой же как у отца. 

Answer 2

Inheritance of Sheep Traits

When it comes to sheep traits such as wool color and ear length, it is important to understand how these characteristics are inherited. According to the information provided, the black wool color is completely dominant over white, while long ears are incompletely dominant over earlessness. Additionally, heterozygous animals (those with two different alleles for a particular trait) have short ears.

Crossbreeding Results

Based on the given information, 124 lambs were obtained from crossing white, short-eared sheep with a heterozygous black, long-eared ram. The question asks how many of these lambs are white and earless, as well as how many have the same genotype as the ram.

To determine the number of white, earless lambs, we need to consider the inheritance patterns for both traits. Since black wool color is completely dominant over white, only lambs with two white alleles (homozygous recessive) will have white wool. Similarly, since long ears are incompletely dominant over earlessness, only lambs with two earless alleles (homozygous recessive) will be earless.

To calculate the number of white, earless lambs, we need to determine the genotypes of the parents. Let's assume that the white, short-eared sheep are homozygous recessive for both traits (wwEE), and the black, long-eared ram is heterozygous for both traits (WwEe).

When these genotypes are crossed, the possible genotypes of the lambs can be determined using Punnett squares. Here is a simplified representation of the Punnett square for the wool color trait:

      | Ww   | Ww
----- | ---- | ----
ww    | Ww   | Ww
ww    | Ww   | Ww

From this Punnett square, we can see that all the lambs will have the genotype Ww for the wool color trait. Therefore, none of the lambs will be white.

Now, let's consider the ear length trait. Here is a simplified representation of the Punnett square for the ear length trait:

      | Ee   | Ee
----- | ---- | ----
EE    | Ee   | Ee
EE    | Ee   | Ee

From this Punnett square, we can see that 25% of the lambs will have the genotype EE (long ears), 50% will have the genotype Ee (long ears), and 25% will have the genotype ee (earless).

Therefore, out of the 124 lambs, approximately 31 lambs will have the same genotype as the ram (WwEe) and will have long ears. Additionally, approximately 31 lambs will have the genotype ee and will be earless.

To summarize: - The number of white, earless lambs is approximately 31. - The number of lambs with the same genotype as the ram (WwEe) is approximately 31.

Please note that these calculations are based on the information provided and assume simple Mendelian inheritance patterns. In reality, there may be additional genetic factors and complexities that could influence the results.