What phenotypic ratio would you expect as a result of a test cross between a dihybrid organism and one that is homozygous recessive for alleles at two independent loci?
a. 3:1
b. 9:3:3:1
c. 1:1:1:1
d. 1:2:1
e. 9:4:2:1
Answer:
c. 1:1:1:1
Explanation:
When a heterozygous individual for two genes is test crossed with a double homozygous recessive individual, the progeny is obtained in 1:1:1:1 phenotypic ratio. This occurs as the heterozygous dominant individual forms four types of gametes in 1:1:1:1 ratio while the homozygous recessive individual would form only one type of gamete having one recessive allele for each gene.
For example, a test cross between TtRr (tall and red) and ttrr (short and white) would produce a progeny in following ratio=
1 tall, red: 1 tall, white: 1 short, red: 1 short, white
Here, T= tall, t= short, R= red, r= white
Answer:
1 and 1/8 teaspoons of butter i think
Explanation:
Answer:
DNA can be described as the molecules which carries the genetic code for every individual. The DNA is made up of nucleotide bases which join the two strands of DNA. The sugar and phosphate form the backbone of the DNA.
Genes are the hereditary molecules which are made up of DNA. The alleles of a gene represent which traits will be carried by an organism.
Chromosomes are made up of genes. During reproduction, crossing over of DNA occurs and alleles of the genes assort independently due to which variations occur.