Sex-linked characteristics (1 Viewer)

[pilota45]

In these notes it states:

 Males only have to inherit a single gene to have the characteristic.
 Females, having two X chromosomes, will have a second normal gene to ‘fall back on’ even if one is deficient ie they have a 33% chance of getting the disease.
 However, males have a 50% chance of getting the disease, as only 1 gene decides what happens. Ie a single recessive gene has the same phenotypic effect as a single dominant gene.

But isn't it meant to be allele? I'm very confused with the difference between the terms allele, gene and where it is located in a chromosome and on the pairs of chromsomes????????? help

 

[HeroWise]

In this context both genes and alleles are synonymous, With that being said.

When we do Punnet Squares: Remember you write down the genotypes (Genetic make ups) of a certain "gene" or aspect of the body. Such as Hair length. The hair length code is a gene. Evenry individual in the planet has it.
Genes are a section of the DNA. And it is the DNA that codes for proteins. to Code for Hair, However, during Gamete formation (Mendels law of Dominance) sets of "segragated" Code or Gene shows dominance over others, and its THIS combination that is an allele to the gene.


so Like for Hair length H is lonng and dominant while Short hair is "h"

HH
Hh these 3 combination are ALlELES to Hair Gene
hh

Alleles are basically expression of different genes being expressed.

A pair of chromosomes or Sister chromatids house SIMILAR Genes but may hace Different coding hence Alleles.
They are in a pair known as Homologous bond. Their genes correspond but is not always the Same CODE.

If u still have troubles hit me up