Observing an incident in which two white cats produce an offspring that is not white may be perplexing if one does not have a clear understanding of basic mendelian genetics. This report will assess this scenario, while presenting basic information pertaining to heterozygotic, homozygotic mixtures of simple traits, and the inheritance of these traits.
A basic understanding of Mendelian Genetics will suffice to explain how phenotypic traits such as skin color, hair color, eye color and other non-complex traits occur. The inheritance principles described by the late Gregor Mendel were elucidated using simple organisms such as pea plants (Eizirik, 2010). It is through this application that Mendel realized that cross breeding of animals and plants could produce certain desirable properties. Previously individuals did execute crossbreeding practices in the farming and animal domestication industry. However, it is Mendel whom determined that an item (i.e. gene) within the parent would impact the outcome and probability of actually obtaining the desired trait (Mendelian Genetics, 2014). The famous punnent-square may be applied to simple traits in which one or few genes are identified as responsible for producing a specific output. Considering the genotype (i.e. X or Y) within the punnent-square for parents would allow the genotype, and therefore phenotype probability to be determined.
During an event in which two phenotypically white cats where; (1) is male and (1) is female, produce different ratios of progeny phenotypes. This is extremely probable when considering the application of the punnet-square scenarios. After constructing a punnent square and assuming that each parent contributes one (1) gene for a color that is white (dominant) and one that is black (recessive gene). Then it is possible for one of these offspring to obtain both the necessary haploid portion of the gene, which codes for the black color.
At this point it is important to assess the scenario, which must occur to lead to this. Both parents must contain a dominant gene for white color (W) and a recessive gene for black color (b). This leads to the genes of each parent occurring as; Wb (expressed as phenotype: White). During mating each offspring will obtain one gene from each parent, to make a diploid set. The ratios will be as follows; WW (White) x 1, Wb (White) x 2, and bb (Black) x 1. An identical process would occur with golden retrievers if both parents contain the same mix of dominant to recessive, genotypic mixture.
In conclusion, simple phenotypic expressions such as white and black fur color are possible event in the event that both parents are white. This of course assumes that the genes for white color are dominant and genes for black color are recessive, and that both parents contain a mixture of both genes, in a heterozygous fashion.