Horniness in cattle dominates over horniness. the hornless bull was mated with three bloods. From mating with a horned cow dawn, a horned calf was born, with a horned cow cow – a hornless calf. From mating with a horned cow asterisk, a horned calf was born. What are the genotypes of all animals that took part in mating?
Let’s designate the gene that causes the hornlessness of cattle as L, then the gene that causes the development of horns in a homozygous form will be designated as l.
Since crossing the hornless bull Vaska with the hornless cow Zvezdochka gave birth to a horned calf with genotype ll homozygous for the recessive gene, it should be concluded that Vaska and Zvezdochka are heterozygous for this trait.
The asterisk is heterozygous – Ll.
Vaska also has the Ll genotype and produces two types of spermatozoa – L and l.
The horned cow Zorka will have genotype ll homozygous for the recessive gene and will produce eggs of the same type l. The horned calf she gives birth to is also homozygous for the recessive gene (ll).
The burenka has horns, therefore, it is homozygous for the recessive gene – ll and produces eggs l. A born hornless calf inherits a recessive gene from her, and a dominant L gene inherits from Vaska. Thus, the calf born by Burenka is heterozygous – Ll.
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