Best answer: Can you have one allele?

When slight variations of the gene exist in the population, each variation is referred to as an allele. Single allele traits are traits determined by only one allele as opposed to multiple. Some traits, such as eye color, can be determined by more than one allele, but many traits are determined by single genes.

Are there always 2 alleles?

When the copies of a gene differ from each other, they are known as alleles. A given gene may have multiple different alleles, though only two alleles are present at the gene’s locus in any individual.

Do males only have one allele?

Males are XY. Since males have only a single copy of the X chromosome, they have only a single allele for any gene on the X chromosome. Males are said to be “hemizygous” for any X-chromosome genes, meaning that there are only half (“hemi”) as many alleles as normally present for a diploid individual.

What is one allele called?

Allele, also called allelomorph, any one of two or more genes that may occur alternatively at a given site (locus) on a chromosome. Alleles may occur in pairs, or there may be multiple alleles affecting the expression (phenotype) of a particular trait.

Why do we have 2 alleles?

Since diploid organisms have two copies of each chromosome, they have two of each gene. Since genes come in more than one version, an organism can have two of the same alleles of a gene, or two different alleles. This is important because alleles can be dominant, recessive, or codominant to each other.

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Are males hemizygous for the Y chromosome?

All single-copy Y-linked genes are hemizygous (present on only one chromosome) except in cases of aneuploidy such as XYY syndrome or XXYY syndrome.

Y chromosome.

Human Y chromosome
Y chromosome in human male karyogram
Features
Length (bp) 57,227,415 bp (GRCh38)
No. of genes 63 (CCDS)

Why are females not considered hemizygous?

Because females have two copies of the X chromosome, whereas males have only one (they are hemizygous), diseases caused by genes on the X chromosome, most of which are X-linked recessive, predominantly affect males.

Where do alleles come from?

One allele for every gene in an organism is inherited from each of that organism’s parents. In some cases, both parents provide the same allele of a given gene, and the offspring is referred to as homozygous (“homo” meaning “same”) for that allele.

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