32.( 12 points)
The sex determination of sheep is XY type, and it is known that its horniness and hornlessness are controlled by the allele (N/n) located on the autosome. Black hair and white hair are controlled by allele (M/m), and black hair is dominant to white hair. Answer the following questions:
(1) Rams with genotype nn or Nn have horns, but NN has no horns; The ewe with genotype nn has horns, and Nn or NN has no horns. If multiple pairs of hybrid rams cross with hybrid ewes, theoretically, the phenotype and proportion of ewes in the first generation population are _ _ _ _ _; The phenotype and proportion of ram are _ _ _ _ _ _ _.
(2) In order to determine whether M/m is located on X chromosome or autosome, a classmate mated several pairs of homozygous black-haired ewes with homozygous white-haired rams, and the ratio of black hair to white hair in the second generation was 3: 1. We believe that it is impossible to determine whether M/m is located on the X chromosome or the autosome based on this experimental data, and supplementary data is needed, such as statistics of the second generation. If it is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.
(3) Generally speaking, there are _ _ _ _ genotypes in an animal population whose sex is determined as XY type when a pair of alleles (such as A/a) are located on an autosome; When it is located on the X chromosome, there are _ _ _ genotypes;
When it is located in homologous fragments of X and Y chromosomes, (as shown in the figure), there are _ _ _ _ genotypes.
The answer to this question is
(1) Angular: no angle = 1:3 Angular: no angle =3: 1.
(2) female: male = 0: 1 female: male = 1: 1.
(3)3 5 7
The above are some questions and answers of a comprehensive science examination paper in the national college entrance examination for reference only.