Acche Marks

The X linked genes are located on non homologous region of X chromosome and these gene do not have corresponding alleles on Y chromosome. Female has two X chromosomes. In female two recessive sex linked genes are required for expression of sex linked traits. If one X chromosome carries a recessive gene for sex- linked … Read more

One example of an autosomal recessive disorder is cystic fibrosis. It’s a genetic condition caused by inheriting two copies of a faulty CFTR gene, one from each parent. Some other examples of autosomal recessive disorders include: Sickle cell anemia Phenylketonuria (PKU)

Crossing over is a process that produces new combinations (recombinations) of genes by interchanging and exhanging of corresponding segments between non-sister chromatids of homologous chromosomes. It occurs during pachytene of prophase I of meiosis. The term crossing over was coined by Morgan. The mechanism of crossing over consists four sequential steps such as synapsis, tetrad … Read more

Allosomes are the chromosomes that are responsible for determination of sex (gender). In humans, they are typically denoted as X and Y chromosomes, with females having two X chromosomes (XX) and males having one X and one Y chromosome (XY).

The cross of F1 hybrid with the homozygous recessive parent is known as a test cross. It is used to test whether an individual is homozygous (pure) or heterozygous (hybrid). Test cross is easy, simple, repeatable and predictable.

An individual possessing contrasting alleles for a particular trait, is called heterozygous. Heterozygous does not breed true for that trait and produces two types of gametes e.g. F1 generation hybrids (Tt). Heterozygous individual is also called hybrid.

An individual possessing identical allels for a particular trait, is called homozygous or pure for that trait. Homozygous breeds true to the trait and produces only one type of gametes e.g., tall with TT and dwarf with tt.

A cross between parents differing in two heritable traits, is called dihybrid cross e.g. cross of pure tall, round seeded plant with dwarf, wrinkled seeded plant.

Mendel’s “Law of dominance is not universal” reflects the complexities in genetic inheritance. Real-world genetics presents instances like co-dominance and incomplete dominance, where alleles don’t strictly adhere to dominance or recessiveness. These exceptions add shade to visible outcomes, challenging the simplicity of Mendelian principles. The dynamic interplay of alleles in these scenarios reveals a spectrum … Read more

The concept “Test cross is a back cross, but a back cross is not necessarily a test cross” highlights differences in genetic approaches. A test cross unveils genotype by breeding with a homozygous recessive individual. It observes phenotypic ratios in offspring. A back cross mates an organism with a parent or a genetically similar individual. … Read more