Question

Two black female mice are crossed with a brown male. Later female I
produced 9 black and brown off springs, female II produced 57
black off springs. Then
i) what inference can you make concerning inheritance of black and
brown coloured mice?
ii) with the help of phenotype given, find out what are the genotypes
of parents​

Answer 1

Answer:

Genotype of parent mice

Explanation:

We may describe groups by the proportions of males, of brown mice, or of brown male mice (discrete variables), or by the means and variances of their weights, lengths, or lifespans (continuous variables).

A collection of samples will usually exhibit some variability in the proportions or means of the characteristics under study. If a sufficient number of characteristics are simultaneously considered, no two mice will be alike. The variability, aside from chance differences between samples, may have either genetic or nongenetic causes. The nongenetic causes of variation in the characteristics under study may be of many kinds, including seasonal fluctuations, differences in kind and amount of food consumed, exposures to noise, light, or humidity, or differences in prior experiences. The genetic causes of variation are simpler, at least in principle, in that they are exclusively the consequences of different genetic contents of zygotes.

Investigators who use mice are concerned with the control of both genetic and nongenetic sources of variation. Some of the nongenetic sources may be controlled by standardizing the management of the mouse colony or, when it is desired, by deliberately imposing two or more different conditions of rearing or treating the mice. The genetic sources of variability may be controlled by the choice of an appropriate breeding system. Various breeding systems useful with mice, their theoretical consequences, and the criteria for choosing one in preference to another